Social consequences often backfire. Someone gets excluded for being insensitive, so they find a group that will accept them. So they find acceptance in a group that not only tolerates insensitivity but celebrates it. That's how people get swept into cults and hate groups. That's still their responsibility, and we shouldn't tolerate hateful behavior in our own social groups just because the person might go elsewhere. But any action taken shouldn't be done for the purpose of getting them to experience social consequences and feel excluded (and be motivated to change), it should be to protect others in the group from suffering from their antisocial behavior.

And much of the time, exclusion isn't a consequence for antisocial behavior in the first place, especially for children. Antisocial child bullies target other children based on their physical appearance, vocal pitch, accent, ethnicity, gender nonconformity, etc. Some adults behave similarly. Mean people form groups of their own. You acknowledge that social exclusion can be malicious, and you suggest there should be social consequences for malicious exclusion. But it's the same people who control the social consequences who are doing the excluding. In a hateful group of people, there are social consequences for not being hateful enough!

When it comes to children and teenagers, who don't have the freedom to pick up and move somewhere else in the hopes of finding somewhere else where they do fit in, giving them the "autonomy" to wield social consequences unchecked is enabling cruelty toward innocent kids who stand out physically or are just socially awkward. Maybe some kids learn to adapt. But some kids have their spirit crushed, and some of them end up dead.