That would be an uncharitable explanation. Surely, you aren't going to also argue that the vulnerable people don't care about others? A charitable argument is

That would be an uncharitable explanation. Surely, you aren't going to also argue that the vulnerable people don't care about others? A charitable argument is that people who cannot get the vaccine for a medical reason probably also shouldn't be around a lot of other people during a pandemic. But with the current absence of evidence we don't actually know why the social answer is different.