Having done community moderation/management/enforcement for years, as a hobbyist and as a professional:

Moderate consequences are a virtue. Minor levels of negative feedback are much more likely to actually modify someone's behavior towards the norm than are major ones. Major levels of negative feedback, more often than not, put someone into a place where they reject your community and its norms, and so are often-but-not-always just a stepping stone to ostracism or expulsion.

Ostracism and expulsion *absolutely* have their place, but minor negative feedback is a must-have tool.