"I welcome sensible arguments for not using English as "work" language - if there are any?"
More than sensible arguments for that (there are none in my view) I'd like to know the point itself you are trying to rise here. This has been an issue for some time already, and it is clear that educating a whole generation of Spanish citizen that were not offered a proper foreign language training in their youth is going to take more than a "regulatory change" so, either you accept it and move along or you just don't fly to Spain and France, but looking for arguments at this point of the game has no purpose other than eliciting a reaction or, as some pommies like to say, "stirring the pot".