Um, except for the fact that there aren't any races that involve both motorbikes and insurgents. I think it's pretty obvious why people are against ramming. It's the the tool of a cretin, which the cretin uses to sabotage the better player. You're skilled. You get a perfect turbo start, you ace the first few corners, and you're leading the pack. A sharp turn is coming up. At this point you have two options:
Option A, you brake for the corner and take the ideal line to keep your lead. The cretin behind you, not knowing how to drive, piles right into the back of you and sends you (and possibly himself) off the track. You're now last, and you have to battle your way up through about a dozen cretins to get back in the lead. Which you can't, because as soon as you pass one, you're once again in front of a cretin and you're going to get rammed off the track again at the next corner. You have now lost the race.
Option B, you take the corner wide, knowing that there are cretins behind you aiming to ram you. In this case you get passed by half the pack and rammed by the other half anyway, because they're cretins who don't know how to drive and they're taking the corner wide even though they don't need to because they're at the back of the pack with nobody behind them. You're now last, etc., etc., you have now lost the race.
It's a no-win situation. Skill is completely irrelevant in standard races, victory is determined purely by whether you happen to come out of a collision better than the person who collided with you and whether the people ahead of you happen to ram each other out of your way or into your way. Or to put it another way, there's a very good reason why in real motorsport intentionally ramming other racers gets you disqualified.
As for people getting mad about it over voice chat, yeah, that is pretty pathetic, I'll give you that. The correct response is to host your own races and set them to non-contact, thereby depriving the cretins of their only tool and assuring easy victory.