WHY ARE YOU SO CREEPY?!

I don't understand dudes that are creepy on Facebook. I submit the following situation for the commentariat:

A few years ago, at an old job, there was a guy that went out of his way to be friendly to me. That was fine; he was super friendly with everyone and it was nice to have someone to talk to during breaks.

After a few months, it did get to the point where I started avoiding him. His attention was simply overwhelming and made me uncomfortable. He knew I was happily married and trying to conceive, but I got the distinct impression that he had a thing for me. He friended me on Facebook and occasionally said hello to me. After I stopped working there, he never interacted with me anymore but we remained Facebook friends.

This morning, I woke up to a message from him on Facebook:

"I just ran across a picture of you pre-hair cut from 4-12-12 and you look so fucking hot."

Uhm. Dude. I haven't talked to you in THREE YEARS. What the everloving fuck? I promptly deleted the message and unfriended him. Why would anyone think that was appropriate? I looked up the picture and yeah, I do look damn fine, but come on. And it was an old picture, no recent comments to put it in my feed - he had to have been looking through my profile and digging through my pictures to find it. SHUDDER. WHY DO YOU HAVE TO BE SO DAMN CREEPY?!