Last I checked, the ban bots exist in default subreddits (like /r/TwoXChromosomes) and there are reason you might want to comment in one of the shunned subs - not that you will usually know a sub is on that list until the bots get you. This kind of guilt by association is horrible.
As far as I can tell, default subs haven't been a thing for many years now. The new reddit UI will ask you to pick topics you are interested in and show you subs related to those. And that UI shows an absolutely huge number number of subs so if you pick your country as an interest, it will show you quite small local related subs for example.
It happens on /worldnews which is a huge sub and shouldn't (in theory) be hyperpolitical. I've even seen it on subs like /nhl that have have nothing to do with politics at all, banning people for posts on other subs that don't align with the mods politics. Not that it matters, Reddit is essentially useless now but at one point it was a great source of information.
r/comics went on one the other day from what I saw.
Basically a mod (anonymous because modmail) telling someone "Republicans are all the racists, say this or continue to be banned." ... in the fucking comics sub.
But to me, mods going off the deep end is just the latest cherry on top.
They killed themselves to me back in 2016/2017(?) when they changed their algorithms to try and stop r/the_donald, it all feels stale now, like it is only updated at most once a day.