For some counter perspective to point 1, I'm a white male in the Bay Area whose interests often place me in diverse groups, some of whom advocate social justice policies. I haven't noticed SJW/PC culture as an actual barrier to socializing and no one I maintain contact with has ever mentioned it as a problem.
Anecdotally, SJW/PC call-out culture appears to have a much more depressing effect on public discourse over the internet where posting opens you to criticism from anyone on the internet.
Are those groups focused on sj polices? If they're groups where that's not the focus, and they've injected those policies. (I.e. let's say a HN user group) That's a problem. How comfortable would you feel stating a disagreement without even mentioning your identity or status? How comfortable would you be in stating the disagreement if you weren't 100% confident on what you were saying?
For communities not focused on policies there's a certain amount of fragmentation along what I would call sj/pc social norms. In my boardgame group, for example, if you intentionally refer to someone using pronouns they do not like you get ejected; in which case you could leave our regular meeting place and walk 4 blocks down to another gathering where that sort of behavior is tolerated.
As far as expressing disagreement goes, the rule is the same as it's always been as far as I can tell: The degree to which a view outside the local Overton Window is expressible is directly proportional to how much the listeners respect your politics/thought process/moral grounding and how far outside the Overton Window the view is. The more the listener respects your politics/thought process/moral grounding, the more radical the idea you can argue to them without being dismissed. Go too radical for someone who doesn't know you well and you lose the listener.
So in direct response to your question, I'm very comfortable stating disagreement on topics that it's socially acceptable to disagree about generally and am comfortable disagreeing about anything with certain specific groups of people. This is, as far as I can tell, the most any society has ever achieved. A Bay Area neoreactionary will be shunned by most for expressing their belief that a woman's place is in the home just as a progressive in Birmingham, Alabama would be shunned for suggesting there's nothing wrong with abortion.
I would go so far as to say that if this level of self-censorship is new to someone then they have been fortunate to spend much of their life in communities in which their views fit comfortably inside the local Overton Window; for everyone else this is normal.
Having the rule about pronouns is what I was referring to. Just having that rule makes people afraid of being rejected from the group from a slip up like that. (Thus creating censorship) Personally, I avoid groups that mandiate things like that or I'll aggressively reject that rule. (I'll let them know that it's a bad rule and I will speak up on it frequently.. will I intentionally treat the people who feel the need to have a different pronoun than what they're percieved badly.. no) However, I realize that I'm different and I don't tolerate bullies.
So I would say first, respecting pronouns is not a rule unto itself, it's encompassed in a more general "be respectful" rule, whose interpretation is informed by our social norms.
Second, for a group seeking social cohesion a certain amount of censorship is desirable. We also don't allow people to casually disparage people of color because if we do those members of our community who are people of color would either leave or cause a ruckus, neither of which we want.
Third and lastly, mistakes are tolerated, we're people not caricatures and know that the pronoun stuff can be difficult to track. If you slip up you'll be given a "look" and a chance to correct yourself. If you don't correct yourself, and continue to slip, interventions slowly escalate from friendly reminders of the form, "hey, please watch what pronouns you use" to longer discussions about why your behavior is not acceptable in this context. We use this same approach for people who use unacceptable language, or have trouble controlling their volume when speaking, it's the only way to keep a group of random people tolerable to be around.
As I stated, you are immediately shown the door if you are intentionally misgendering someone. So if someone tells you they want to be called she/her/hers and you very emphatically refer to them as he/him/his a dozen times in three minutes you get the boot. Just as we'd throw out someone who was being extremely rude to our members in a more conventional manner.
I feel that we're getting down in the dirt with one particular groups' conventions.
On an interpersonal level, I respect the overton window. On a group level, I'm highly concerned with it. It caters too much to the needs of the over sensitive.
I'm on the level of if you're abusive towards other members, you've lost the support of the group and a rule about that is fine. Setting the line at "don't abuse other people" is generic and supported to all people.
But when you codify a rule about pronouns, you're just giving an endorsement to the most oversensitive member that would be 'victimized' by that 'crime.' (Are they going to be easily set off by mistakes?, unintentional misusages during excitement) It also communicates to everyone that it's something you will be rejected and ostrisized from the group over. (That's where the silencing effect comes in).
Anyways, that's my 2c and what I've seen about some groups and how I run my groups to be inclusive.
Anecdotally, SJW/PC call-out culture appears to have a much more depressing effect on public discourse over the internet where posting opens you to criticism from anyone on the internet.