Because his stutter was alway very minor, it has become indistinguishable from his mental decline and it's impossible to identify it in his speech anymore. It's hard to say what the intent was behind the flag. Because of his speech, or because "that's all folks" references his dropping out as the nominee. The "if this was you" question can't really work here because his situation is very specific and it could mean multiple things. Obviously no one wants to be made fun of.