Keep within the User Guidelines
and you shouldn't have any problems.
The infraction process gives people lots of warning if they're stepping over the line, such that being banned requires a concerted effort to do so. Except for spammers, they get no chances.
I'm not going to discuss specific cases here, but it would have had nothing to do with their issues, or point of view. If the posts which caused them to be banned fell in the realm of trolling, flaming, or non sequitur, then they would have been removed.
If you have any questions or concerns about it, feel free to send a PM to a moderator, and we'll try to address them as best we can.