I feel for you; but hey, what are ya gonna do?
The unbalanced games can be a real pain but you don't have to take it if you don't want to. Feel free to leave or just lock your brakes and wait for the game to end. (That way you can still get points for finishing the game. If I happen to spawn in while you're getting camped on I'll do everything I can to get up and clear the air. There are some other high ranks who will try to do the same. If I manage and you can get airborne feel free to go for a sneak. The worst thing that can happen is we'll lose.
Unfortunately some players like to be bullys. Kero Zen is a perfect example of someone with skill and experience who just doesn't seem to care who he shoots or how he gets his kills. He used to make me mad but now I just have fun chasing after him every time I see him. If he manages to get over the spawn point... ugh.
But hey, why stress. Lock your brakes and watch for a bit. Take note of what they do that you don't like and remember not to be that way. Besides if you stick with it, your skills will improve and maybe someday you can return the favor!