Yeah, it is. Partly because when the movement was invented they hadn't thought about all of these things, and partly because identity political movements tend to to gather all the groups they think are oppressed together into one homogeneous group, it makes it seem like there are more of them and separates them more from the perceived majority or "oppressor" group. They've done the same thing with "people of colour" - according to the activists, that's just everybody who ain't white. Which is an awful lot of people and variety. But it's done to make the white identity seem even more separate and privileged, and everything that isn't is supposed to unite together in some sort of underdog brotherhood even if there's a hundred different cultures and values and racial identities in there. It's ridiculous, really.