Aggression and swearing are perfectly acceptable. What isn't acceptable is if you express a negative opinion regarding certain divisions of culture and society. The media pretty much sets the standard on this using a sliding scale of 'offensiveness'
This sliding scale is dependent on who you are; eg Nazi slurs are pretty much 'up there' and will definitely get you in a lot of bother. All other races, cultures, religions, sexualites fit into this scale. If you're White, Male , Heterosexual you're pretty much down the bottom; you're fair game.