Armed Scientist,
my hat's off to you for handling a 101% douchebag with aplomb.
When I went to buy my first pistol (thanks to Sarah Brady, bless her heart)in 1994, there was another douchebag looking at rifles. Having seen me choosing between the Glock and the Browning, he told me "I don't have a use for pistols, because I don't ever plan on shooting someone else."
Respecting my elders, I quietly responded "I am happy you feel that way." End of story, he shut the hell up. I got my Browning. It's been a sweet pistol.