I'm assuming most people here have Netflix and do not have cable. Here is Starz' dilemma: Let's take all cable subscribers and consider them potential Starz customers. They can A. Pay $15/month to get Starz or B. Pay $8/month to get Netflix + Starz. They would all choose B.
Now let's take all the non-cable subscribers and call them potential Starz customers. Starz technically wants to keep this too, but they would lose out on all the customers in the 1st scenario, which make them more money. Thus, their unfortunate decision.
As consumers, we need to wage war against cable companies by not subscribing. Unfortunately, this is difficult to do considering quality sports programming is dominantly viewed via cable and the like.