Confirmed, boards are full of Lee Sin haters

Some people do feel that if he's unfun to play against, why would they want to play him.

Also if you are already working on learning mechanics for other champions why add a quirky one that is difficult to play?

I admit that I don't care for Lee Sin. I think the way he is protected by RIOT hurts the game and impedes the development of the community. I have no interest in learning to play him for that reason. I'd rather pull out a champion that I plan on eventually using in ranked matches than a champ I wouldn't feel right playing.

The fact that most Lee Sin's I've played with have been terrible only further reduces my interest in playing him. I have heard that there are some incredible "big plays" that can be pulled off with him, but I'm a team player and the few plays I've seen have appeared to be solo acts. I'd rather play a champ I can win with than him.

TL/DR: because I have no interest in playing him.

xD haters gonna hate, particularly those who can't dodge a skill shot.