While the discussions about him most definitely not being Mashiach and a novi are very important, I believe that that is not the main point that many of us are trying to convey.
He lead a large group of people along a dangerous path where the belief that their shitah is the only correct one, and that things accepted or rejected for hundreds of years are now to be rejected and accepted, respectively. He constantly justified his and his chassidim’s actions, regardless of how the world saw it.
It is thus no wonder that the level of tznius in Crown Heights and other Lubavich strongholds is far below the level of all other chareidi groups, and the mixing of the genders is atrocious. (Can you name me any other chassidic group where a woman speaking to a group of men is accepted. There are probably small groups of Lubavich chassidim who find this reprehensible, but it is accepted by the vast majority.) If everything we do has been okayed by the boss, and he will bring the geulah any day regardless of what anyone else thinks, then everything is muttar.