My crazy neighbor dug up over 100 Stargazer/Asiatic lilies in full bloom from MY yard, threw away the ones he didn't like and kept the others to replant in his back yard. He is a 60+ retired professional, he's got a lot of boats and rv's (aka, he's NOT poor) and we're in an incredibly prissy, "nice", neighborhood. I had to dig through his garbage can to salvage my own plants! It's not like I gave him permission to do this -- he just did it. (My boyfriend was ready to beat the crap outta Mr Crazy over this).
Mr Crazy saw nothing wrong with this behavior. He chats with me like there's nothing wrong, and even talks about how much his wife loves the lilies.
I can totally relate to your disbelief with the Christmas light thief. People are crazy.