messed up nursey rhymes that i'm sure we all sang

http://mindtwister138.blogspot.com/2006/07/nursery-rhymes-are-evil.html I used to sing the baby on the tree nursery rhyme but I've never actually thought about it, but now that I'm reading the words and And Then There Were None, this is scary. How come there are so many things that are twisted and messed up like this, exposed to little kids already? So they can have a sense of the cruel reality that they live in? There are messed up nursery rhymes like these that seem happy but are actually very nefarious while there are the Disney stories that lie and make every ending a happy ending.