A lot of people are reporting this problem. My guess is that the algorithm analyzes not only your previous comments, but the types of videos you watch. If you watch a lot of videos made by people that youtube deems "problematic" you're probably more likely to get your comments shadowbanned.
Its easy to get around the censorship tbh
I think it's getting a lot harder to do so. I think Google's algorithms are getting better at detecting alt accounts of (shadow)banned users. No, not just on the obvious things (IP address, cookies, etc.) but based on searching and browsing patterns, typing style, etc.
Sure, you can change your ip address (or get a VPN), switch to another browser (if you were using chrome), and create another account, then intentionally change your behaviors so that google's algorithms doesn't detect you as an alt of a shadowbanned user, or otherwise flag you as a wrongthinker and thus someone who should be shadowbanned...but considering the amount of effort involved, very few people will do this to begin with, and out of the few that do, most will get shadowbanned again anyway. There's also the fact that new accounts and accounts from VPN users will be judged more harshy by the algorithm. Hell, a lot of shadowbanned people probably don't even realize they're being shadowbanned to begin with.
And this is why big tech censorship is so effective. Sure, a small percent of people will slip through the cracks, but that won't matter in the grand scheme of things. If you whitelist group A and censor group B, even if some more clever and determined members of group B circumvent the censorship, they'll still be dramatically outnumbered by group A, thus group A will control the zeitgeist virtually uncontested. And that's one of the many reasons winning the culture war was such a cakewalk for the SJWs. There's also the fact that the masses are now strongly in favor of mass censorship, and acts of censorship against wrongthinkers is always met with uproarious cheering. 10 years ago there would have been pushback from the masses, but the times have changed.
Face it, the wild west days of free speech on the internet are long gone, and they're never ever coming back. Free speech as a concept is dead, and the few that are still active proponents of it are mocked by the masses, or just called nazis or whatever.