This has been a huge problem since the beta a couple months ago. I was hoping they would have at least improved it since then, but nope. Player contact needs to be either removed, or heavily tweaked so that it isn't so terrible.
Player contact in any game that has online racing is generally annoying, mostly due to people intentionally ramming others in the race. However, in this game people aren't going out of there way to bash into others, it's literally unavoidable due to how many racers there are. On top of that, the player contact is incredibly buggy. In my last Mass Race, I tapped the back of someone's bike and was sent full speed to the left, into a rock. Also, it causes players to have a 'rubber banding' effect where they look like they're lagging. Not to mention the extremely annoying and repetitive noise it makes. Everything about it feels 'off' and broken.
I asked people what they thought about this in a couple discord servers, and 90% of people agreed that player contact completely ruins the fun of mass races. Unless you manage to get past everyone and keep a top 3 lead the whole race, you're almost definitely gonna get bashed into walls, trees, out of checkpoints, etc.
If you agree that Ubisoft needs to do something about the player contact in races, please upvote this post so they see it, and leave comments about your thoughts on the matter.