Well, he's insulted a lot more than one disabled person with the terms "loser" and "stupid"; of course, there's what he said about McCain's physical disability caused by what happened to him in Vietnam. While running for the nomination, the list of disabled people he's insulted also includes Serge Koveleski, Charles Krauthammer, and Justin Chappell. This is not a one time thing for him. See also the remarks he's made about disabled folks on the apprentice. I think it's fair to characterize his remarks as "all disabled people are losers".