Re: The man is correct
Of course learning Latin in particular sets a pretty good foundation for learning most of the Romance languages. My wife studied Latin to the Swedish equivalent of sixth-form level, and now she tells me that her perception of the Romance languages is as essentially dialects of Latin, which makes it pretty easy for her to switch between them in conversations. It's quite scary when she does.
It also sets a very solid foundation for general language skills, even if does sometimes lead to needless pedantry about the splitting of infinitives...
Or, to look at it another way, your objection to learning programming to GCSE level could also easily apply to the other core subjects. Not everyone needs to learn French. Not everyone needs to learn chemistry. Not everyone needs to learn physics. They do anyway, because it's a general education. Specialisation happens afterwards.