Alot of this has alot to do with Psychology, and basic instinctive behavoir. (as demonstrated in this video: http://www.youtube.com/watch?v=SzWazsPCqlA )
Alot of people's actions are bourne of instinctive survivalist behavior (without them realising it), as the human being is a herding animal.
Being accepted in the herd is an instinctive thought, which is down to survival again (1000's of years of the caveman clan/tribal living has created this, as being on your own in ancient times was rather tricky). So doing anything that the majority of the herd doesn't do/approve of gets certain treatment.
In short: Sheep mentality, or "Sheeple"![]()
Although true, things like this gets you the tag trainspotter.