Nursery Rhymes

Does anyone know the meanings behind some of the nursery rhymes out there? Kaylee recently got a "big sister gift" of a collection of little nursery rhyme board books. She is obsessed with them! She literally reads them all day long and asks for us to read them at nap AND bedtime. Some of them are quite disturbing. Here is one that is in her collection, I have never heard of it, but it goes like this

Ladybug, Ladybug fly away home,
Your house is on fire and your children are all gone,
All except one, and that's little Ann,
For she crept under the frying pan.
Thats just a little too frightening for me to read to my 2 year old!

Then there's "Ring Around the Rosy," which is about the Bubonic Plague.
"Humpty Dumpty" what's all that about? Kaylee's book shows an egg sitting on a wall, but in actuality the rhyme was written about a cannon named Humpty Dumpty in the English Civil War, but now it is portrayed as an egg. Who comes up with this stuff?
"There was a little girl" the rhyme is all good until the last line.
I was talking to my sister-in-law about this subject the other day and she told me was a "diddler" is. Like in the nursery rhyme "Hey diddle diddle", I couldnt believe what she said it was......and children SING about that?
"There was an Old Lady", this rhyme is a little more modern, so it really doesnt have any history behind it. But the lyrics crack me up. At the end of each verse it says "perhaps she'll DIE." Yet again another song that doesnt sound too comforting to the ears of a 2 year old.

I say that nursery rhymes need a make-over! I have decided! Im not the best rhymer in the world, so I think that someone, anyone needs to come up with something more enjoyable to teach our little ones.

Does anyone know any other nursery rhymes that have strange meanings, or strike you as odd?