I’m over here rooting for Mineta to pull through with the dirty jokes because it’s the one time he can get away with them. Let him have his fun for once Iida, he’s gonna get beat by one of the boys for everyone perverted comment here on out.
Oh yeah I can see this. All Might is a bit depressed because he thinks he can't do anything for the students anymore so Deku proposes the song as a tribute to him.