No. The abortion analogy is terrible. Abortion is a muddy issue because it pits the rights of the mother against the rights of the fetus. The crux of the argument basically comes down to whether one believes that a fetus should have the same legal protections as a human. If the mother is forced to carry the pregnancy to term, she loses the freedom to make her own medical decisions, if she is allowed to terminate her pregnancy, then the fetus will never be born. We have not yet devised a way to resolve this conflict.
Contrast this with the gay marriage debate. There is no conflict. Gay marriage does not affect its opponents in any capacity. A married gay couple does not infringe on anybody else's right to be married. Opposition to gay marriage is completely arbitrary and rooted in discrimination in all cases, there just isn't any reason why one should care, and even less of a reason why the government should take that judgement into consideration. Any religious, traditional, or cultural opposition to gay marriage is completely moot since marriage is not even real thing, it's simply a legal status with the same name as a historical tradition.
My point is about bigotry, not gay marriage. The muddiness of the issue is part of the point, we all have opinions on rights that should exist, and it is easy to throw the word "bigot" at anyone who disagrees with us. Therefore a blanket dismissal of all forms of bigotry easily becomes a straightjacket that limits our ability to think. Take that one step farther and you wind up with silliness such as an unwillingness to discuss obvious gender mental differences such as the differential performance under the Piaget water level test. (See http://books.google.com/books?id=ocl5AgAAQBAJ&pg=PA130&lpg=P... in the likely event that you don't know what I am talking about.) And that leads to things like Larry Summers getting fired over fallout from his discussing the best available research on a controversial topic.
Therefore I'm against a blanket, "You're not allowed any trace of bigotry." Strongly against it. It limits people's ability to think.
Now I can see you responding that this example has nothing to do with gay marriage. So let me give a real example tying that one.
My opinion is that homophobia ties to the uncanny valley (see http://en.wikipedia.org/wiki/Uncanny_valley for what THAT is) which is the feeling of revulsion that virtually all of us have for the "almost human". (Different people having different definitions of "almost".) Having broached the topic, we can discuss emotional reactions to other races, disabled people, various disfigurements, and the ways in which horror movies play on the natural phenomena.
But wait, what can of worms did I just open? I suggested a connection between widespread homophobia and an innate phenomena that causes the vast majority of humans to feel revulsion under the right circumstances. And it is a pretty strong revulsion - seeing that which you dislike will, like it or not, be about as palatable as stepping in a pile of shit. This really does affect others. (If you argue that it affects others because they are bigots, I can't disagree...but a lot of people are so affected.)
Pretty much everyone who I've really had the conversation with has wound up realizing at some point that there is stuff which they personally respond with revulsion. And some of that stuff results in their having trouble not discriminating. You can try to consciously try not to act on that revulsion, which usually leads to an overreaction and reverse discrimination. But the roots of at least some sorts of bigotry are something that seems to be built in to pretty much all of us - certainly me included.
But if you've conceptualized anyone who has any trace of bigotry as unequivocally bad, then this is not a conversation that you're able to have. Because at some point you're going to have to face ways that you resemble people you don't like.
And THAT is an example of why I don't want the mental blinders that keep me from even trying to think about homophobic people in terms that are more sophisticated than, "They are awful people."
(For the record, I am straight, I am not homophobic, and I voted against prop 8. Also my sister has some gay friends who wish I'd reconsider the "straight" bit...)
Take that one step farther and you wind up with silliness such as an unwillingness to discuss obvious gender mental differences such as the differential performance under the Piaget water level test
So what? The veracity of scientific studies is not at issue here. My point is that unlike the abortion debate, there are no muddy waters in play here. It's unequivocally wrong to deny homosexual couples the same legal rights as heterosexual couples, there is just no other reason beyond bigotry to deny them the freedom to be married. I'm not saying that we should hunt down all the bigots, I'm saying that bigotry alone is not a satisfactory justification for any position and is easily rejected as such.
But wait, what can of worms did I just open? I suggested a connection between widespread homophobia and an innate phenomena that causes the vast majority of humans to feel revulsion under the right circumstances. And it is a pretty strong revulsion
Ok... Perhaps that's a possible explanation, it's also a completely irreverent one. I am revolted by the sight of individuals who put 4 inch gauges in their ears, but that personal disgust doesn't justify an attack on their right to start a consensual legal relationship with another consenting adult. My disgust doesn't matter. Their relationship is none of my business. Laws against gay marriage are in a similar vein to sodomy laws, namely, a bunch of hateful, entitled, "revolted" traditionalists who want to leverage the force of the government to prevent consenting adults from living their lives in a way that affects nobody but themselves. It's simply wrong. There are no two ways about it, nobody gains anything by keeping homosexuals away from marriage, it's only purpose is to deliberately deny homosexual couples the satisfaction of inclusion in a legally recognized institution.
My point is not the veracity of scientific studies. My point is that a blanket rejection of all forms of bigotry creates an emotional barrier to useful discussion of those studies. Whole avenues of research are cut off as verboten.
Furthermore what you are stating is your personal opinion that a sense of revulsion and disgust is not a valid source of moral opinions. But now you're opening another can of worms. Preliminary results from brain research have identified 5 different subsystems in our brain that underly opinions that get called "moral". Those 5 systems are:
1. Recognition of suffering in others.
2. Reciprocity (the golden rule).
3. Hierarchy (respect for elders, power systems, etc).
4. Coalitionary bonding (loyalty to your group, patriotism, etc).
5. Purity (praising cleanliness, viewing things as gross).
In general liberal moral systems tend to focus on the first 2 and conservative moral systems tend to focus on the last 3. As much as you think that revulsion and disgust are not proper bases for moral opinions, most of the world disagrees with you. And if you want to live in a democracy, you're going to have to live with results that you don't like. Furthermore no amount of complaining on your part is going to change this inconvenient truth.
Contrast this with the gay marriage debate. There is no conflict. Gay marriage does not affect its opponents in any capacity. A married gay couple does not infringe on anybody else's right to be married. Opposition to gay marriage is completely arbitrary and rooted in discrimination in all cases, there just isn't any reason why one should care, and even less of a reason why the government should take that judgement into consideration. Any religious, traditional, or cultural opposition to gay marriage is completely moot since marriage is not even real thing, it's simply a legal status with the same name as a historical tradition.