Don't switch to them. Even if you wanted to be a Fem Viera or Male Hrothgar but don't support the race being female and male only don't switch to it. Don't make alt characters as the new races either.

You don't have to unsub, although that might be more impactful. (I doubt it) Just don't play the new races. Don't buy any more fantasias. Or buy one and switch to a race we already have. If 0 people support the new races then (maybe) they will release a statement that they will unlock them in a future expansion.