No, it's f***** not.
Babies cry because they can't communicate well enough with words to get those around them to do what needs to be done. Adults are supposed to be better than that. https://twitter.com/zeegunner1/status/1254056640699039744

There is a difference between what someone deserves and what we as as civilised people should do to them.

A racist may deserve a slap but by definition these are crappy immoral people who think they didn't deserve a slap, so they will be more likely to be violent with their racism, because YOU, not them, are the one who made violence the medium of communication by crossing that line.

Please understand... I'm not saying this from a position of being some hippy pacifist. There's no line I wouldn't cross to protect others. But if you punching a racist today makes him more likely to beat up a minority person tomorrow, you're not protecting anyone.