Superman has renounced his American citizenship. That's what I read anyway. It's a complicated scenario, and I don't even want to begin to imagine the complexity of his legal status, but presumably he's an American citizen only the guise of Clark Kent. So Superman has always been in my mind an international figure with his primary base of operations in the United States. Of course the Fortress of Solitude exists outside those boundaries and if anything is his home that's it. So it's complicated I guess.
Lots of folks are choosing to get their ire up about this, but then they seem to be the same folks who make a business of raising ire. I don't read Superman comics, so I'll only know what the press tells me on this. I'll be interested to see how it develops.