I'd suggest cognitive dissonance, the theory suggest its the subliminal (so most of us are consciously unaware) process wherein a person is asked to change an opinion or pick a side or team, or us (team Axis) v.s. them (anyone who doesn't own an Axis). It may also involve the defense of a choice a person may have made in the past when they purchased a different brand of rifle, so they get defensive or even angry if challenged, again the process is somewhat subliminal but can the level of response manifested can as we all know be very passionate. The same process where by fan's cheer for a local team and pride in them winning and angry when they lose, all in all it's just human nature and all very superficial. To someone who isn't aware of these processes taking place in people when confronted by a strongly counter opinionated person the confrontation can be very confusion and off putting. When people learn about this process they may tend to be less opinionated on a topic where they don't have a broad base of experience to make an educated guess.
Then again it could just boil down to the way the horrible Axis stocks feel.... (kidding ; )