I've been known to drink Budweiser. Does that mean that I believe that women will suddenly find me sexy and the Swedish bikini team will appear as I pop off the bottlecap to lavish me with scantily-clad attention?

You are conflating the marketing copy of the company with the intentions and motivations of the users. Just because something confirms your most cynical expectations doesn't make it true.

Ashley Madison has absolutely no idea whether any particular user, if they are married, is on there to do anything with their profile other than browse, or whether their spouse knows they are on there, or for that matter if a couple is browsing the site together as part of their joint fantasy life, or if they are in an open relationship, or a number of other scenarios that have no impact on you and really provide no basis for you to cast judgment about their motivations--especially in an absence of evidence.

See again, my cite to David Brin's article on addiction to outrage.

Uh, what? How is membership in a website that is known, markets itself, and is designed as a cheating website not evidence of the intentions and motivations of its members? Of course membership in Ashley Madison isn't irrefutable proof that a person is looking for an affair. But how is it also not good reason to believe that he/she is?

You can use a gun for killing, and it's marketed for that specific purpose. Does owning a gun make you a killer?

No, because I'm talking about intentions and motivations, not actions. I said it's reason to believe that someone has intentions/motivations to have an affair; I didn't say it's enough to believe that someone has had an affair.

The reputation, marketing, and design of guns is a good bit more varied than Ashley Madison's. But yes, buying and learning to use a gun shows a certain intention or willingness to kill. It may be to kill a deer you're hunting or to kill a person in self defence, but in general it's evidence of a certain willingness to kill.

You're making a lot of false assumptions. You could be the owner of gun, intending to fire it against inanimate objects only. Like a paper target at the gun range.

One could even have bought it out of simple curiosity.

Yes. And you could be a member of Ashley Madison who's just curious, or who's doing a documentary for Al Jazeera, or who's trying to see if your spouse is on it.

I was speaking generally. I said that it's reason/evidence in favour of a conclusion. I said that it isn't proof of it. Those kinds of general rules and presumptions are useful for all kinds of things and in all kinds of ways. Or do you think that our judgements should be entirely composed of perfectly comprehensive and universal rules?

You are confusing marketing with actual use. Cf "to serve and protect".

Not surprised to see the overlap between the anti-cop and pro-adultery crowd.