I don't think leaving and tweeting about how you feel is a very useful response. It could lead to a form of evaporative cooling[1] and cause the behavior of the group to worsen. It may be better to put pressure on the group to change. Find someone who is in charge and complain about the behavior you find inappropriate and encourage other people who find the behavior inappropriate to complain as well.

[1] http://lesswrong.com/lw/lr/evaporative_cooling_of_group_beli...