Personally disagree. Empathy doesn’t necessarily mean agreeing, it can also mean understanding why the other person is thinking like that, while still disagreeing with them.
Being clear, I agree that shunning is the correct path, but it’s not because “you can’t have empathy for people who lack it”, it’s exactly because you understand that if you don’t shun them, they’re never going to change. The utopic end goal is that people understand why they’re being shunned and start rethinking their choices. Of course, if they don’t and they want to keep being shunned that’s still a positive for society, but we should still hope for them to change. It’s sort of like the (stated, unfortunately not factual) purpose of prison.