Wow, I did not know that people actually do associate the outcome of WW2 with being "coward" gamers. I am not saying anyone does that here, but wow. Those are the real cowards... :/
I have no idea why French gamers specifically should be called names and flamed, though some people I know claim that the French are not "that" good in English, and therefore not being able to cooperate efficiently in team games. But then again, I never played LoL.