The problem with boycotting a network with shows you don't like is that it doesn't really work. If you don't like the shows, you wouldn't be watching already, right? So there aren't any viewers actually lost and ratings remain the same. Those crappy shows, are embarrassingly enough, fairly highly rated.
The thing about TLC is it's a privately owned network, so they can do what they want that they feel makes them the most advertising dollars and whatever they want to do. Just like National Geographic...or excuse me, "natgeo." TLC actually used to be, quite literally, "The Learning Channel" and was run by (I think) NASA. It was privatized in the 1990s. That is what happens when you privatize things and is probably THE most powerful argument for public/government funded tv. If you want valuable content on your learning channel, it needs to be motivated by providing good, informational content, not viewers and advertising. In this country, they mostly aren't compatible.