Some thoughts:
1. Isn't the enforcement of "skin-deep kindness" still better than allowing people from blowing up anytime they want? There's a concept of law officers stopping 'gateway crimes.' If you can stop teenagers from doing the small stuff like shoplifting, then they'll learn to not do the big crimes when they're adults. The same applies to bad actors in a community. By stopping new users from committing the small crimes, then you can repress some of them from committing more egregious acts.
2. Community attitude is built over a thousand small steps AND the few big steps. You're not going to build a sense of community by only banning one member and ignoring all of the other members, not will you earn the respect of your members by moderating the masses but not taking decisive action on the truly disruptive actors. It's not one or the other. You need everything: strong terms of use, moderation team, community monitoring and user reporting, clear escalation procedures, etc.
3. Humanity is not born kind. Or polite. Or respectful. It's learned behavior taught by parents, schools, and society. This breaks down online when users can escape those social constraints. The question then becomes: how do you remind users to act like they would in public?
4. Invision doesn't do nearly enough in thinking about the behavioral psychology of users.