dick pics

This morning I received my first (and God may it be the last) dick pic. In other words some random guy taking and sending me a photo of his erected penis. In sheer shock and disgust I instantly deleted it and blocked the sender. I now regret that as I should’ve tried to look up the Instagram handle and outed the bastard. I don’t get it. Why do men do these sort of things? (Yes, it’s fairly common, I’ve just been spared, until this morning.) What kind of response would they be expecting? Is the purpose to get me to feel disgusted and awkward (successful) or do they really think a woman would get exited to see an amateur photo of a very average man’s stiffy?? Right now I’m just trying to shake it off but the question remains: why the fuck!?