Just as some songs not written for kids are perfect for kids (hi, Spare the Rock, Spoil the Child; hi, Greasy Kid Stuff!), some poetry not written for kids is perfect for kids.
Or that's the assertion of Lemony Snicket (occasionally known as Daniel Handler), who wrote a wonderful article for Poetry Magazine. His article, All Good Slides Are Slippery, features illustrations by Chris Raschka that are every bit as vibrant as Snicket is droll ("Poetry is like a curvy slide in a playground — an odd object, available to the public — and, as I keep explaining to my local police force, everyone should be able to use it...").
The article is definitely worth a read, and, I agree - those are some excellent poems to read to your kids, regardless of your stance on slides.