The majority of the French gamers that I know have no issue with either speaking *or* understanding English, but will only opt to speak English when they know for certain French is not an option.
As for the topic: I don't really understand what the problem is, isn't one of the great things about humanity the multi-culturalism (and thus also the diversity of languages)?
I think the English (-speaking) need not worry, not only do they receive the majority of the servers (even though none are advertised as being *English*). They also have a way higher chance that, in the case they do end up on another language server, that they'll stil be understood when trying to speak English. Which can't be said for for instance Russians/Spanish/... that speak their language on an *English* one. Sure some'll understand it, but the ratio will be less high.