As a moderator on another board, a pet forum (sometimes emotion is high and they can be the worst) i've had to step on someones free speech if it got profane, threatening, advertised without permission from site owner or if they basically posted nonsense or a question that had recently been asked and addressed that took up valuable board space.
I try to be fair but "free speech" does not equal free for all. There is a structure set by the owner which every mod agrees to upon joining as well as common sense and etiquette (netiquette, if you will). I always encourage regulars to step back and cool down if it gets heated with someone who is fairly new and disagrees that ends up accused of being a troll (happens more often than not) or even long time members who just happen not to like each other to examine what about the post or argument is getting to them and come back with a later time presenting their response if they feel it hasn't been resolved or addressed rather than a post after post after post flame war resulting in getting a time out or have their post edited ot deleted. We don't like to have to step in and do that either, we'd rather you come to your senses and mod yourself. Attack the post not the poster, that's one motto.