If Facebook cared about the mental health of its customers it would remove public likes. One of the big crushers of self-esteem is seeing your own post get 5 likes while a friend's gets 50.

FB won't, of course, because it's a big part of what keeps people engaged. Getting a lot of likes is a big dopamine hit. If no one sees all your likes - well that's not as satisfying. If no one sees likes they are probably less likely to "like" something. I get that, but it's still a sad bottom-line based decision.