I guarantee the worst of that will T Cut out buddy
It's a total pain in the arse but it looks worse than it actually is I am sure!
I bought a white bumper from a scrapyard for my MK6 Escort van after hitting a bollard down the kart circuit.......paid peanuts for it because of all the scratches........yet when I fitted it and T Cut it.......it looked brand new! I kid you not! The majority of those marks I bet are from a white car........use the T Cut and it will remove the other cars paint from the bumper.
Good luck and hope you get it sorted mate. Sorry about the dimwit who did it though.........shame on them!
Smitten Jim