Cuz he is a meme, no one takes him serious except 2ch and school children. Most Russian opposition is retarded and traitorous they do everything opposite of the goverment even if its something that the russian people agree with. 
Just look at Crimea, like 90% of russians agreed with the joining of it even some Putin haters. But you have retards like Navalny who would say that no they shouldnt have done that. Russian politics have an immature democratic culture. There is literaly no worthy opposition in Russian due to retards like Navalny taking the prime spot and not enough smart people who will compromise with the government on certain issue and press hard on others while being productive.
This is why you perceive that the election are rigged there is no one to choose from realistically, as well as the government wont allow dangerous turn coat retards like Navalny to rock the boat for no reason except to get power for himself.