Combining your brand name with minimal oversight is a poor choice. TEDx has a very strong signalling mechanism to me, which is "I couldn't get my ideas accepted anywhere else, but I think they are important enough for TED".
For most things, opening up is noble. But not for a brand -- can you imagine Apple allowing other companies to use their brand for experimentation? Or Coca-Cola?
Those brands are for-profit and opening up may indeed not make sense financially.
TED is a non-profit, and their goal is to build an efficient platform for sharing ideas (and not only theirs). In this regard, opening up makes total sense, even if brand damage is a risk. (hence the respect)
The whole point is staying alert to see these mistakes, whether they come from TEDx organizers or from TED itself because nobody is right 100% of the time.