The peer pressure badge awards users for deleting their own bad post.
Some users like to game the system. Just recently, I saw a post where a user posted an intentionally bad question. The user later declared that this was because they wanted the peer pressure badge.
Additionally, "peer pressure" doesn't sound particularly friendly.
Although I realise that abuse alone is not a good reason to remove something, I really don't think the peer pressure badge adds anything good to the system.