It's the same reason
It's the same reason some people have to have a really loud motorcycle, a pickup truck that's jacked up to like 10ft off the ground, or some really fast sports car: Insecurity.
The psychology of this gets a bit deeper than I can say without being heavily censored by the forum software... But let's just say this is the way the socially inept overcompensate for the insecurity they feel about the size of their manhood.
That is a vast vast oversimplification of the issue, but I don't have the time, and most people wouldn't want to read it even if I did. I will say that if you have a broader curiosity about people's behaviors, you should consider studying some psychology and sociology. Just don't make the mistake of majoring in them in college, because sadly there's really just no job market for people with those degrees, even if we weren't in a sputtering economy.