It depends on the situation.
If he/she is getting physically attacked by a racist who is alone then yes knowing that no one will jump on me.
If they’re being racially abused verbally then no because they can ignore and walk away without getting hurt.
If they’re being attacked by group of skinheads then no but if I’m in a safe spot like inside a locked car then i’ll get everyone’s attention to scare them off by pressing the honk button. If not, take pictures of them then send it to the police station (unlike US, they take it seriously here).