Nothing is stopping you from expressing yourself however you want - just elsewhere, if you can't follow the rules.
fwiw, this very website has its own code of conduct: https://news.ycombinator.com/newsguidelines.html
It focuses on different things than the Wikimedia one, but it's fundamentally the same thing. For both of them, I'd suggest that if there are things that you feel are detrimental, you specifically address them.
Making an empty comment like "new wave of censorship" achieves nothing except saying "I don't like the rules". In which case, fine, there are plenty of other places on the Internet.
That argument doesn't work if it's a monopoly or a near-monopoly, which Wikipedia is. Also YouTube etc.
The other reason it didn't really work out well is that people need an audience. Voat was and is much smaller than reddit, so they had less reach. What I'm trying to say is, is that it's not a technical challenge, those have been solved already. It's people with extreme views who want to be able to express themselves where those views are not tolerated.
I'll join the protests once they actually start censoring, but if it's just like hey: don't be an asshole or you can just be an asshole somewhere else... I'm fine with it.