"Don't beat up on yourself" .... wrong??

[Alambil]

Why is there an "on" in that sentence?

Also, is it a heinous crime to say "Don't beat yourself up"?

Beat up on is a very American expression... like "hate on me".

I don't personally think that it is a heinous crime to say "Don't beat yourself up", but I'm sure there are people out there that do.

The colloquial American expression is 'beat up on' eg 'Three boys followed me home and beat up on me' so in a US context 'Don't beat up on yourself' is logical if slangy.

Not acceptable in the UK IMO though.