Guilty of western bias. But should be a bit obvious that I didn't mean smaller languages, or languages spoken from people that are usually not here discussing with us. But if it wasn't obvious before, I am making it explicit now.

Third, of those gendered languages, they don’t necessarily agree on what gender things are. In the video, they mention that “A Key” in German is masculine and in Spanish is feminine.

How different languages gender a key (or a chair, or teapot, or whatever object) is not really relevant for a discussion about genders in people.

And I don't even mean that to defend anything, just trying to explain why people apply genders to babies. And how people just do that for convenience, and how that's not relevant as a "permanent" gender.