Nope. I can't articulate how much this would annoy me. That's her moment, and he's inserting himself into it. If he wanted to propose on her graduation, then a quiet moment, later in the day, just the two of them, would have probably been a lovely way to round off what was no doubt a wonderful day for her. But on stage in front of all those people, screams to me, 'never mind your huge achievement here, created by your own hard work, lets put the spotlight on meeeeee and this super important question I couldn't possibly wait to ask you.' It's like he doesn't want her to have her moment about her. Very unpleasant.