A game has nothing to do with shaping a community. Online etiquette has gone down the tubes over the years simply because people feel like they can hide behind a screen act how they want and get away with it because there are no direct
repercussions. If someone is uncomfortable with something and speak up they are immediately teased, made fun of, or trash talked. I've seen it numerous times in parties/guilds.

Personally if people start acting rude or immature I just ignore them and hope they will eventually go back to Call of Duty or other such game where that kind of behavior is expected. In games like this things seem to go much smoother and a lot more fun when people are polite, nice, and helpful.

Just my two cents, but I don't believe a game molds the community. I think its the community of the game and what type of behavior is allowed that creates a good or bad environment.