And why do villains keep going back to NYC?? You're gonna run into the FF, the Avengers, Strange, the X-Men, Spidey......basically 90% of the superhero population lives within like, six miles of each other.
Go rob banks in Chicago, guys!!
Doom.....I dunno, by MU standards wouldn't the general public just see him as the equivalent of a nuclear foreign power? Most of Doom's biggest moments seem to be (and Im no expert!) things that the regular person would never hear about (it happens in hell, or space, or the future, or a broken reality where history was remade) and the heroes aren't gonna cause riots by announcing that, for a little while, Doom became God and changed everyone's lives. I mean, a nuclear foreign power is scary enough and people do seem to be concerned about Doom, but at least you know the Avengers and other heroes are capable of containing him. Or so the average person (maybe?) believes.