Inequality though isn't on/off, and there are degrees. The current existence of inequality isn't a logical dismissal of attempts to prevent it worsening.
And of course, the danger of AI is much greater than just inequality: it is the further reduction of all human beings to cogs in a machine, and that is bad even if we all end up being relatively equal cogs.
Because it's true? We already had a world war between autonomous AIs called national militaries before they (mostly) learned that total conflict doesn't result in them getting more resources. And autonomous AIs called corporations exploit our planet constantly in paper-clip maximizer fashion. The fact that they are running on meatware doesn't help at all.
And we see those as problems. But they were constrained by being executed by humans. Now the AI fans want to make more and more actually autonomous ones executed by machines? The problems would be orders of magnitude bigger. They can do far more at scale. They can perfectly recall, process and copy all information they’re exposed to. And they don’t have a self preservation instict like people with bodies do.