That's a little unfair. The exact status of the immigrant is still vague and he had been in the US legally on a student visa in the first place. If the mayor were heterosexual and his amour a foreign woman, of course, he could marry and all would be well (barring other legal issues. That's also the case, by the way, for me and my HIV. If Aaron were a woman, I'd be American by now). Then another instance in the news:
Raul Hernandez, a gay man who defected from Cuba in 1993 to live in Brazil, had hoped to obtain permanent U.S. residency under the 1966 Cuban Adjustment Act after he arrived in 2000... But following a lengthy application and appeal process, Hernandez, 40, who lives in Arlington, Va., was turned down for admission under the Cuban Adjustment Act in 2005 because he’s HIV positive.
There's something poignant about the US discriminating against a Cuban exile because of his HIV. And something more poignant about president Obama enforcing it. As he still is.