[aidenn0]

Firstly, I can say that I definitely would not be offended, since people have said that about me, and I wasn't offended.

Secondly, we are talking about a performer while performing[1] Sharing personal reactions (both positive and negative) to public performances is, IMO, well within the bounds of polite discourse.

1: This is harder to distinguish when the actor's name is "Fred Rogers" and the role is "Mr. Rogers," but the original comment referred to "Mr. Rogers" rather than Fred Rogers and used the phrase "especially while singing," so I think it's a safe assumption here.