How would you do this? Abolishment is to put an end to something by means of law. We can abolish slavery. We can abolish the death penalty. In a future world, we might could abolish nuclear weaponry.
But we can’t abolish thoughts. You can’t make it illegal to think something. Well, I mean, you could put a legislature together and pass a law, but nobody would take it seriously. Laws need to be enforced. You’d have to hire honest-to-god Thought Police in order to grant your wish.
You can try to abolish racist / sexist practices, but you could never abolish racist / sexist thought. The closest you can get really is to make it illegal to study certain things in universities.
So let’s answer that question. If I could wave a magic wand and eliminate one or the other from the world, I’d go with sexism. As much as I hate racism, sexism is much deeper-rooted and has worse effects on the world.
But practically speaking, the social change necessary to get rid of sexism is just too much to ask humanity to bear at the moment. I’ve yet to even hear a plausible approach to fixing the problem, that’s not already being carried out. We can push it out of our workplaces, out of our home lives, out of our own minds, but sexism is way bigger than the segment of society that wants to get rid of it.
Sexism is literally everywhere. Racism plays by rules. Everyone knows its wrong, and overtly saying racist shit will get you pilloried pretty quickly. Sexism on the other hand, people like President Trump can say baldly sexist shit and, instead of heaping censure on that person, everybody then turns around and squabbles over whether it was actually sexist. “Locker room talk” indeed.
We can agree on what racism means. We can’t agree on what sexism means. We have a better consensus on climate change than we do on sexism.