I don't believe that you've had to argue this far to defend your point. Treating others as you would like to be treated is the golden rule of society.

When I play games like Rocket League, a game where you depend on your teammates, I rarely say anything if people play badly. Others will say things to me if I play badly and that sometimes makes me play even worse depending on my mood. Sometimes I play worse because they actually made me care less and sometimes I play worse on purpose because they were a real asshole and they deserve a loss.

It's pretty obvious that antagonizing and disparaging your teammates is generally a bad plan anywhere.