After some thinking, I think that Charles Lee decided to sell his coins due to conflicts with LTC and his ownership of Coinbase. Due to regulations and legal concerns, he most likely had to choose one over the other. I suppose that he chose Coinbase over LTC as a long term project.

He may still believe in LTC, but perhaps this was how he would get the most value out of both projects. I still think that LTC is a great coin, and I'm coming back around to the idea that it has a good future.