“Gender ideology” is as real as the boogeyman is real. It’s literally a conspiracy theory the right invented to scare themselves.

It’s a thing but not in the way he means it. Trans acceptance and traditionalist views of gender are both gender ideologies. He’s using the word ideology the way propagandists often do: describing an opposing view as an “ideology” to contrast it with his favored view, which he means to imply is simply The Truth™ and therefore above any ideological concerns.