I don't think that's quite fair, I think there are reasonable reasons to be for state rights.
Or, in my own words, it's less than I favor state rights and more that I disfavor federal rule.
Federal rulings are winner-take-all. It doesn't matter if 49.9% of the country disagrees, everybody is now bound by the new rule. There is no fallback for them; they can't move to a city or state that has the rules they want.
Being bound by rules that you don't agree with, that your city doesn't agree with, that your state doesn't agree with breeds resentment and culture wars.
We're a country of 300 million people with vastly different backgrounds and beliefs. We are unlikely to reach a national consensus on contentious issues. We can either rule by tyranny of the majority and piss off everyone that disagrees, or give people more self-determination by running things state-by-state where their vote is worth like 50 times more than at the national level.
I won't pretend it's a panacea. Terrible things have been done in the name of state's rights. I don't agree with what Alabama is doing, but I do understand this outcome is important to the people of Alabama. They should have as much of a right to direct their government as anyone else. Even if they want to do things I don't agree with.
California or New York are likewise free to do what they want. Frankly, they could probably offer some kind of publicly funded "state relocation" program to give people from conservative states the funds to relocate, and they'd probably profit off of it.
I also think most of the federal rights crowd is disingenuous. I didn't hear anyone complaining about state rights when California legalized weed or gay marriage. Many states are still defying the federal government with legal weed.
Really, I think whichever side has a majority in the federal government supports federal rights, and the loser supports state rights. Federal rights are popular among liberals because they've been successful at getting the rules they want (for the most part until very recently). Everything is well and good when the tyranny of the majority is on your side.
I think if that flips and conservatives become dominant at the federal level, state rights will become much more important to liberals.