Oh! So this actually might be caused by bad net code. I remember years back during horizon 4, or early on when 5 released, people would play online races with friends, and a good portion of the time, the ramming wasn't actually intentional. Both people would record the race and one friend would see the other randomly stop or go flying and the other person would see their friends' car send them off course.

The game just thinks the other cars are in different locations than they should be. On the other players' screen, it's possible they didn't even see you next to them. It can appear that you were behind them the whole time.

It's why I wish they would offer a ghost mode where you can't ram, but can just race each other. If they can't make car interaction accurate, then I don't think they should bother with that feature (or at least make modes where it's optional)