I'm sure Murphy did this for the irony of having Kai in the same prison as Manson, but yes--Kai would either be locked up in Michigan or, if he were convicted of federal crimes, be in a USP somewhere.
I work in the political field, so I view most politics from a more nonpartisan lens regardless of my own political leanings--most of it is theater conducted solely for the purpose of getting officials re-elected. Yes, the ones you like and think are true believers, too. I think that made this season seem rather ridiculous and hyperbolic to me, and it made it really hard for me to get any sort of tension or "horror" from it, because I personally don't buy into all of the shrieking drama of either political extreme, and find it all rather silly. I was rolling my eyes and laughing more often during the first half of the season than Murphy probably intended. And I know I've made this point before, but I never bought that any of these people would follow Kai other than maybe Meadow and Winter. Kai is an average looking, marginally articulate, creepy weirdo, and none of these people who followed him fit the profile of people who join cults (abused, abandoned by their families, etc.)--especially not Beverly or Ivy. I just didn't buy into much of any of what happened this season, which threw the whole thing off for me. Not scary, not engaging, and not believable. It's a shame, too, because this is one of the few seasons where the plot was actually fairly tight from start to finish.