Because 1. that term is thrown around so often and so loosely-defined now it is sometimes losing its meaning, 2. nobody was intentionally trying to upset anyone, especially back then, and 3. not everyone agrees with the concept as a whole to begin with. Regardless of your beliefs I don’t even fault e.g. christians for only believing in biological male and female, as that’s what their book says and you’re not going to change everyone’s mind so easily or at all.