*Membership spots not really limited!
You're the Master of Magnetism, you can manipulate the Earth's magnetic field to redirect any nuke harmlessly into the upper atmosphere. All you have to do is stay close to Mom and everything will be fine.
You're still going to roll over and do as you're fucking told? Might makes right, and your might rivals the government's
You are using Magneto, a villain, as an example on what to do while trying to prove the X-Men aren't villains.
Utopia is a sovereign mutant nation isn't it? Besides, Iron Man had legitimate warrants for his fellow avengers who refused to comply with registration. There's the hypocrisy.
If Utopia is a sovereign nation then the X-Men should stop setting foot in the U.S. without their passports.
Iron Man was right though.
Also, Utopia is a sovereign nation because of threats. I doubt they are recognized by anyone.