Dear lord! (AKA, how do I get into these things?)

I am generally a nice person.  I don't like to make people uncomfortable.  I tend to take my lumps.  I also might let people say things to me that are wrong/inappropriate, because I fear telling them they are wrong would hurt their feelings.  And yet, I tend to do nothing to guard my own.
I could write a novel on that one idea alone.  (And, yet, I'm not).
Social Media.
Ah, how I love thee.  How it connects me with those snotty girls from high school and clients that I really don't want to know what I'm doing on the weekend.  And, the random 'creepy guy.' Yes, You know the ones.  The ones that say vastly inappropriate things when they obviously know better.
You know, the ex-boyfriend from high school who spouts off, "I know why I still think about you all the time." Um, because you're creepy and haven't gotten over some puppy love from 13 years ago? Or who still has a teddy bear from Valentines (still 13 years old!?!?!?!?) Do I have things from past relationships? Yes.  I have one photo of an old boyfriend with his parents.  And a drop.  Which means something totally different for me.  And has nothing to do with the actual relationship.  But, am I tracking this guy down on Facebook to tell him so? No. Nope, don't even think so.  'Cause that's creepy!
So, what's creepier than an old BF finding you? How about a guy you've never actually met.  Yep.  almost 3 years ago, I was sitting on my couch being bored and this guy found me on MySpace (That was back when MySpace was cool.  OK, cool-ish.  OK, probably on the way out.  I was a late adaptor, kill me.)  He was a writing major at the same school I went to.  We had a few things in common.  It was nice to have someone to talk to.  But, that was it.  I was not interested in him AT ALL.  You know, being happily married and all. He started getting out of line.  And I quickly set him straight.  I was married and was not interested in him in that way and I enjoyed talking to him, but that was it.  It made me uncomfortable.  If Brad had gotten on my MySpace account (not that he snooped, but I frequently stayed logged in so he could have pulled the page up and seen it if he wanted) and saw the crap this guy said, I would have been blamed.
This guy calmed down and things were cool, but we stopped talking as much.  Actually, it dropped of completely.  Which was great for me!  At some point, he found me on Facebook.  I was hesitant, but he never even said hi to me, so I thought it was fine.  Until I get a letter last week.

I had just uploaded some cake photos, so I guess that had prompted this.  Nothing out of the ordinary.  Nothing lude.  So, I replied.

I was cordial. Nothing detailed.  I was hesitant, given the past. And he quickly replied with this:

Ewe.  Why?  WHY?  WHY??? I mean, he opened with talking about his impending nuptials.  And then drooling over my photos.  Gross.  I so want to forward this to his fiance.  Who is on Facebook and has all this "I found the best guy ever" written all over her wall.  She should be warned.  But, I wont because that would be meddling.  But, I didn't reply.  I wouldn't even know where to begin or what to say.
I mean, who does this?  And WHY?!