Eh… it’s probably not so much that they are demanding their language be spoken…

More a case of the tourists are probably being dickheads in general and the locals have had enough of their shit. That and the locals would like to be able to enjoy their own beach without having to wade through masses of tourists.

I mean, it depends where you go in Spain right. If you're working in an office in Madrid and someone gets annoyed that you don't speak English that's one thing, if you're working a restaurant in an area that makes all its money from tourism, then surely it makes sense to make those people bringing in the dough feel comfortable.