I agree that it depends on the circumstance. Particularly, it feels more like patronizing if we highlight an accomplishment for a particular reason that the party in question finds embarrassing. Maybe Johnny doesn't want to be applauded for doing his homework. But if he doesn't mind, then there is no harm to Johnny.
But there may be another, unintentional harm: the harm to the ego of everyone who isn't Johnny. They may feel hurt that their own accomplishments weren't highlighted. They may even try to defend this hurt feeling, by saying something like "So? We did our homework too. Johnny's not special. Don't you care about us?" But the point of the accolade was never to down-play everyone else's achievements; it was merely to recognize Johnny's. But the ego gets in the way, and prevents us from letting someone else have the spotlight. We see ourselves as smaller when our peers are raised higher than us, and this makes us defensive.
But there may be another, unintentional harm: the harm to the ego of everyone who isn't Johnny. They may feel hurt that their own accomplishments weren't highlighted. They may even try to defend this hurt feeling, by saying something like "So? We did our homework too. Johnny's not special. Don't you care about us?" But the point of the accolade was never to down-play everyone else's achievements; it was merely to recognize Johnny's. But the ego gets in the way, and prevents us from letting someone else have the spotlight. We see ourselves as smaller when our peers are raised higher than us, and this makes us defensive.