......- she said that on the internet, they call people like me stalkers.

dude if you're a stalker, I'm afraid to think what I am....
(My 13 year old daughter just begs me to not embarrass her while we are out in public....)
Ahh!
Classical parenting

He would be a stalker, if the "stalked" person doesn't want to be "stalked".
I'd explain it to my kids by saying "it's just a game of a group of adults".