If you made a Venn diagram of self-proclaimed libertarian’s beliefs, the center would be empty. That is the practical definition of libertarian in today’s world.

Could you not lay this same criticism at the feet of the other political parties as well? Due to the way plurality voting works, the incentive of each party is to be as large as possible (at the expense of group consistency), and the incentive of each individual is to align themselves with only one party (at the expense of accurately expressing all of one's views).