Ultimately, the answer here lies in greater dialogue with men and women, over what they actually want in sexual communications.This reach some of these men, those who are genuinely not understanding some sexual differences.
Women understandably complain about this for two main reasons: "Men are GROSS" is the most common explanation that women have for this. Do they really think I'm going to magically want to have sex with them now, after seeing their penis?
Smartphones, texting, email and online dating are the current vehicle for this behavior and sexual dynamic, but let's not pretend that this is a new issue.
The underlying sexual processes and dynamics have always been with us.
People who are offended and grossed out at such images would like them banned.
They want men to understand that such behaviors are rude, unacceptable and should simply stop.
But, this requires for women to have the safety to be honest about their sexual interests.