Why were you scared? I find most bikers to be rather down to earth individuals to talk to. Most are mellow and really cool. The Biker Gang types are some times less than desirable and ones not to really tangle with.
But just because they are little rough on the exterior, dosn't mean they are inhuman. My comment would have been "I have them bright like that just so not to suprise people behind me."
He probably noticed this cause alot of after market tail ligts tend to be dim even at night, and in the day you can't see ish. Pople who ride bikes tend to notice this alot more seeing they have a little more at steak when it comes to rear ending a car.