There is a case to be made about some kinks; someone with a humiliation kink (often exercised by being led around on a leash) is getting close to the line (if not crossing it) of non-consensually involving others in their scene.

Though I agree with you that just "wearing a leather harness" is a pretty innocuous, and in general people don't require consent for their wardrobes in public. And on top of that, going to pride and then complaining about other attendees is at best a bit silly and at worst completely missing the point.

I think consent here is trivial to understand when you talk about a kink most everyone understands: naked skin.

Being naked isn't per se a sexual act, obviously. I don't need anyone's consent exposing my body e.g. going swimming in a lake.

On the other hand, someone getting off exposing theirselves to strangers is involving unconsenting strangers sexually.

Wearing a harness or demonstrating the lifestyle perfomatively does not include strangers in a scene.

Playing in public for e.g. public humiliation on the other hand, is involving unconsenting strangers sexually.

It's really not that hard. These concern trolls have an agenda.

"wearing leather harnesses and chaining each other up" is a bit different than just wearing a leather harness in public. But also how hard is it to just be civilized when you're in public? I don't need you to wear a suit and tie, but at least have some decency.

It's once a year. And the idea is to fight back against stigmas that have made such behavior illegal, or grounds for being fired, or having your kids taken away.

I don't know who needs to hear this, but having gay sex in the privacy of your home while you're tied up in a leather harness should not result in those consequences. Display of similar behaviors at Pride are intended to tell the larger world that they aren't going to stop being themselves. People need to grow a thicker skin and get used to the idea, so that Pride isn't necessary any longer.

I personally find that the most uncivilized people always come dressed in suit and tie.

Like any other thing, it depends on why someone wears it. A trans man wearing a traditional man's cut to celebrate getting top surgery at pride is probably not what you had in mind though.

Hm, I'd personally go with a bow tie.

Nothing wrong with those.

Boundaries that delineate these celebrations have been explicit in SF at least since I started going in the early 2000s. The intent is to create a safe space for participants. Within that realm at those times the boundaries represent the presence of that space and that "normal social conduct" is no longer the norm.

Who defines "civilized" and why does that seem to particularly exclude specific categories of people?

It's especially bad in the BDSM scene. Grown adults who act like the kid in school who would go around telling other kids they weren't following the rules. They treat victimhood and white knighting like a job.