Probably because she's a lot younger and still has plenty of time for her politics to get much worse.

But yeah, Bernie deserves more criticism for many of the same reasons. Both are Dem entryists presenting themselves as "democratic socialists" when the limits of their imaginations are somewhere in the neighborhood of FDR New Deal liberalism and the right wing of social democracy. Bernie deserves even more shit than AOC does for promoting a sort of US-American social imperialism, consistently supporting the growth of the military-industrial complex.