Correct and moral does not mean he'd have a problem with wanting a man -- maybe problems showing it due do the way such things were perceived in his own time but Steve has always been very open minded and accepting (unless we're talking Ultimate verse).

Like I said its a interesting idea of Steve having a thing for the armor itself and more Iron Man than for Tony but I think you over empathized Steve feeling 'ashamed' and that others would be disappointed in him. It was hard to tell if he meant disappointed because he wants Iron Man or the fact that he's masturbating.