“Bad-faith” isn’t about opinions themselves. Full-stop. Moderation isn’t about trying to ensure everyone has compatible opinions, it’s about ensuring that those opinions can be debated respectfully.
“Bad-faith” from a moderation context is:
0 - violating our community guidelines. That’s an easy and obvious one.
1 - posting something with the specific intent of riling up the community instead of participating. This necessarily requires some way to tell that the user likely does not believe what they are saying.
2 - a consistent pattern of taking the “devil’s advocate” position on multiple topics. We’ve had several bad-actors do this specifically - they always took the contrarian point specifically to rile up the community.
3 - Repeated feigning personal involvement with topics - that improbably, a user is part of every minority, that they’ve done every thing, that every issue is personal for them. We’ve had bad actors do this specifically, as well.
4 - Traditional sealioning - coming into a discussion, demanding that it go only one way, and that people expressly refute their position, dismissing all others.
Every one of these behaviours should be flagged, not responded to, because responding only serves to further the aims of the bad-actor - they want to create a derail, to rile up the community, to force you to spend energy on their claims, to make more work for the mods. By instead flagging the behaviour and not replaying you deprive them of that.
Lastly, If we started banning people for being snide we’d have almost no members. 
People have strong and acerbic opinions. The key is those opinions need to be about others opinions, not others themselves. The line is drawn when someone attacks other people, not other opinions.
