Shit, isn't that basically what Apatow said? He said it's ridiculous that people are offended, and basically, he just finds it funny. Add to that the other stuff (the dick being utilitarian and not all that great to look at, sexism by the people controlling this shit, American attitudes on the depiction of sexuality) and I think you have all the reasons.
But shit, even in something like Any Given Sunday, you know they had that locker room scene with the idea of using that as comic relief.
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