If you’re an XXist, that’s currently in vogue and so therefore it’s understandable. Even the Prime Minister of Canada calls himself an XXist, and depending on your point of view that might count as a significant endorsement.
We all start out as being what becomes a typical XX (whatever that means to you, the particular form is orthogonal here), but for XYs a chemical reaction happens, turning innies into outies and a bunch of other stuff, some of which shows up right away when you are birthed, and some of which turns up later. Sometimes the chemical reaction doesn’t happen in an XY, and so they effectively become equivalent to an XX but remain chromosomally XY, really mostly a technicality then. Sometimes an XX can develop XY features at menarche, including the one you’re probably thinking of.
We end up being similar in some ways – like the head typically goes on top, for example. But we grow differently and end up different in others. I think we should not be surprised to see XYs favouring auto mechanics and XXs favouring nursing. It seems to me that XYs typically favour logical-mechanical thinking and XXs typically favour emotional-holistic incorporating, and though they can each get into the other modes, they typically don’t live in the other mode – perhaps tomXYs are that way, which is why many XYs flock to such. A few XXs can play hockey with XYs, and occasionally cars and even trucks with “You just got passed by a [young(-at-heart) XX]” decals show up at shows.
XY and XX brains are differently shaped, but not dramatically so. More interesting might be the connection between XXity and youth. Tangentially, in Russia there was a fox breeder who wanted foxes as docile as dogs, so he bred them for gentleness, breeding only the ones that would most tolerate his approach. But their coats got all spotted, their features getting cuter as they got more gentle, so they were useless commercially. (More in this Robert Sapolsky lecture (links to 1:05:46), from where I heard of this.)
I think that the XX form in its youthful ideal reflects something of that on the inside as well as the outside. Not that there aren’t many XXs, thinking of the ones in their ultimate form, who have done seen some [things] in the days of their time, and know well many things about the world. Many XXs have their eyes open and speak of what they see, and they should continue to do so. There is no necessary limit in being an XX; it’s more that the natural imperatives attendant to so being have consequences that result in, among other things, the highest attainments of strength and intellectual horsepower belonging to XYs as a rule (see weightlifting and chess if you would like raw competitive examples).
The problem with XXist policies is not that XXs have no place in places. It’s more that even perfectly equal treatment does not portend equivalency. In fact, even preferential treatment doesn’t! Wouldn’t it be good, if an XX is in such a place, you know they actually belong there on their own merit, not just because they’re a person who has an innie? (Although, in the light of typical XY preferences, this is an asset characteristic to be sure.)
Furthermore, policies that systemically take effectual puissance away from XYs are necessarily deleterious to the whole. You want the naturally puissant in roles that demand it. It just makes the whole world and all the functional organizations in it much better. Capabilities matter.
It’s not the case that every XX’s place is the home, and some can even be found in particle accelerators. They even go into space sometimes. (How often they go into my space I leave as a mystery to the reader.) Whatever they do do, they are lovely creatures indeed, and should be cherished as such.