Overuse of the banhammer is not limited to left-y subs and the dreaded "SJWs". Happens frequently on all sides. /r/the_donald will frequently ban for comments made in other subs, as will /r/conservative. Culturally conservative subs like /r/TrueChristian or /r/European will ban easily as well. Of course, some of the lefty subs will too. Some ideologically focused subs, like /r/kotakuinaction, will allow dissent but most of it will get so viciously downvoted it might as well be censored.
And you know what: I don't really have a problem with that. Wanting to keep your political sub, left or right, focused on a particular ideology, without the distractions of debate from those completely opposed, is not a bad thing. Happens all the time in the real world. The DNC is not going to allow Ted Cruz to give a speech, nor is the RNC going to invite Bernie. Your church, assuming you have one, will probably not be inviting atheists to say "God doesn't exist" from the pulpit.
And you know what: I don't really have a problem with that. Wanting to keep your political sub, left or right, focused on a particular ideology, without the distractions of debate from those completely opposed, is not a bad thing. Happens all the time in the real world. The DNC is not going to allow Ted Cruz to give a speech, nor is the RNC going to invite Bernie. Your church, assuming you have one, will probably not be inviting atheists to say "God doesn't exist" from the pulpit.