Not just them. The wiggles all of it. They are made to "baby sit" Not to teach or anything else. Kids learn cheesy songs about sharing and waiting their turn. Becoming good little brainwashed monkeys who don't put up a fight as an adult. Mr. Rogers and the such I grew up on taught you right from wrong and the basics you needed to enter school. The best children's show of all time is... Pee Wee's Playhouse for many reasons. IT taught you so much about everything that you couldn't help coming away from the show feeling you learned something.
I agree, teletubbies and all sorts of shows like that are brainless rot, its the fact that adults choose TV as the primary entertainer and educator of their children that its so dangerous.