Can't say you'll be likely to get a warm welcome in the current climate- okay, that wasn't...really an intentional pun. Problem is, superpowered people - and that includes Asgardians - aren't too popular right now. Humans are afraid of the collateral damage from all the fights the Avengers have been in.

[Including someone's invasion that wrecked a bunch of Manhattan, cough.]

The Avengers are essentially disbanded, half of us are fugitives from the law in over a hundred countries right now, and it's illegal to be an unregistered superhuman in those same countries.