Truth...
Penis size is a big thing for men... Think perhaps this is a response to pressure placed on men by society? By the 40 Women's Magazines with headlines like "Is Your Man Right For You?". "What Is He Doing Wrong". or even simpler "Bigger is Better"
Tbh i don't actually care about those reasons. I would rather own a Ferrari that a broken 1988 Celica... Similarly i would rather have a Big Penis as opposed to a smaller one. Men are not as complex as women are when it comes to sexual things (Generalization i know) so we tend to distract ourselves with these sorts of things.
Ultimately does it really matter if we are obsessed with it?