yeah, some of them are crappy...but at the same time (as most teachers will tell you), it often doesn't matter what a child reads as long as they're READING.
I would try to get my child to understand the silliness of something if I thought it was important, but otherwise, I say let them read what they like so they develop a love for it.
_________________________________________________________ *moment of silence for all those lost & those yet to be found*