Enola Gay Damaged at Air & Space Museum Opening

maybe there's no such thing as a bad visitor to a museum.
As in "Mommy, why was that man so upset and why did he put a dent in the
airplane?" "Because a lot of people died in WWII, would you like to read
about it?"

Hear hear! Everything is a teachable moment, and is best handled by explaining
that people differ, and some overreact by expressing themselves in
inappropriate ways. I often go look something up so I can explain it to my
kids, or someone else, and wind up greatly extending my own education on the
topic. And learning about the reasons people disagree with my point of view is
also very educational.