There are such posts about each and every platform out there. In addition to not knowing what's the ban frequency, there's also no info in those complaints if they got banned for a good reason.
Last winter people got fed up with antivax-dewormer-nomasker bullshit and a lot of subreddits just took the trash out, so those complaints you saw might just be be those dumbasses.
I'm not saying there aren't annoying powertripping mods on Reddit, e.g. r/Linux, but there always tends to be an alternative subreddit one can use.
The thing about users getting entirely banned from a platform is that they aren't able to complain anywhere near to the forum about unfairness. It's all done in stealth.
Platform algorithms now often do a lot to keep dissent about platforms themselves and partner companies out of sight. It's pretty crazy how companies that publicly advocate equality and fairness serve to undermine speech when it's about their business.