Wow Youtube has really gotten ridiculous with their copyright bullshit, that's the only thing I can see that they could use as an excuse. Maybe it sounds too close to "Discovery Channel"? Or it's not considered family friendly enough? (that is apparently a new policy now).
There really needs to be a competitor to Youtube, since as long as they have monopoly they'll keep being able to pull off crap like this. idealy said site would need to be outside the US. The US is too insane when it comes to IP laws.