Yes, they are.
Because you're arguing about the "main cause" of the Civil War.
Either the Civil War was about racist slaveowners trying hold on to other human lives. Or it was about the was about the right to secede.
Now, I'm gonna in turn argue with everyone else that it was indeed about racist slaveowners trying to hold on to human lives, but that the wrong people lost. You see, the federal government is a group of slaveowners, and their Federal Reserve System (which took power just around 1920s, with a federal income tax in 1913 and inheritance tax in 1916)
has held us in chains for nearly a century, gradually tightening them, until today we feel them with ridiculous food and gas prices.
Do we have states rights? Oh course we do! They are guaranteed under the Bill of Rights, which the founders refused to ratify the Constitution until it had. Why not? Because they were worried that things would be as bad as Britain who invaded their homes, told them what they couldn't say and couldn't write, disarmed them, took away their freedom to worship, etc. This should send off warning bells that I'm talking about this, but you seem to want unfreedom, so let's explain something. A war doesn't give you the right to take away other people's rights, any more than losing to a spoiled child at Parcheesi gives them the right to ride on your back for the next ten years. The issue of slavery was settled because this is the stated reason behind the Civil War. But the North immediately followed it up with the 14th Amendment (ratified under duress), and a number of other unconscionable Amendments (including one to basically pay themselves).
State rights are laid out in the 10th Amendment, and states rights are a good thing. It means that if you don't like how Texas does things with regard to abortion, marriage, or treatment of gays, you can GTFO and go to a state that does. You don't have to care how Missouri votes on the homeless, because Portland Oregon understands how you think. And there are plenty of blue states.
If it doesn't look like it, this is because most of middle America hates you. But most of coastal America is quite liberal, with about 4 or 5 states swinging back and forth.
Here's a good example of a state's rights. Each state has specific laws about drinking. Some allow it even as a minor, but only if served by parents. Some allow it as part of religious customs. Some have dry counties. Some have rules about how restaurants have to have full meals and not just a bar. Others must make a certain percentage from food. Still others have BYOB restaurants.
That you don't like states rights means you're insufferable and think that everyone should think like you and do things your way. That's the mentality of a 9-year-old, not of someone who I assume has been at least college educated. So let's turn the tables. By this logic, if I have all the power, I get to slap you around and force you to pay a "bulmabriefs144 tax" for not being bulmabriefs144. Sounds fair, right? National law that says you gotta do that, so you'll do it, right? No? Then states rights are legitimate, and only people who live in my state of mind have to do that.