He or she doesn't need to do anything. If it bothers them it's their thing. They didn't come here to ask for advice on how to perceive One Piece. I love OP and it's comedy but this stunt left me scratching my head. If that's the best he could think of, ok, but I won't pretend it was awesomely done.
As for Usopp CoC, I thought most of the people were joking about it, me included.
But if anyone else foams from their mouth because of Usopp, I'll be seriously concerned.
If I think about it, it's almost like the opposite of Conqueror Haki. His enemies don't pass out and foam because of his overwhelming presence and awesomeness. They pass out from sheer disbelief at how hillarious his methods are. Effective yes, but hillarious. And in the last fight he made Sugar pass out even though he was completely beaten.
It's like he has a Capitulator Haki. Color of Capitulation.