States' Rights

I raised a question in the comments section to a post below, then decided it might be worth an item of its own: How come the people who are so quick to cite federalism issues when a state law prohibiting sodomy is on the line hardly ever bring it up when the issue is a state university's admission policies? Yes, I know, there's no dubious constitutional right to privacy involved in the affirmative action case. But if states' rights outweigh that business about "equal protection under the law" when the issue is sodomy, you'd think that more than a few federalists would decide the same logic applies with affirmative action. If not on constitutional grounds, then perhaps on decentralist principle. No?

I'm not staking out a position here, just posing a question. Do any of the people who believe Texas' sodomy law should have been fought in the state legislature rather than the federal courts feel the same way about Michigan's system of racial preferences? Why or why not?