It's a similar question that AMD fanboys ask Nvidia/intel guys. Why - are - you - an - Nvidia - fanboy? You know the prices on Nvidia are outrageous compared to AMD, yet you buy them anyway. We all heard it. I feel it's more about comfort ability, customer service, and experience. When someone finds that sweet spot and comfort zone with certain products, it's hard for them to switch it up to a different company and give it a shot. Then they hear the flack and attacks from other people claiming that the other company is pure garbage. So now you have the pressure from other users (a lot of times those people haven't even had the experience to try AMD or Nvidia, and are just trolling for nothing) pressuring them to try something new. Finally, fear. The fear to try a new company, even though many claim you will get good results... Why risk it? What if you don't get good results? Now you have to RMA the stuff, wait for you money to come back, re order the parts you should have purchased because that is what your conscious told you to buy, but you gave them the benefit of the doubt. However, we just don't know unless we try, but it's hard to try if we don't know. Gambling is huge in this market. For some, it's not worth it.
It is better to stick with what you know is good, and are already comfortable with. Some people, though, take it to the "next level".
Edit: Within a fanboy, to them it's best to hide their "fear" and to show everyone that trying the "opposing" team would not be the right move, because there is "flawed performance in AMD"
OR the "prices are too high, and you can get this awesome AMD processor and just overclock it and get the same results." Both are victims of fear because they cannot give themselves a chance to try the other "team" because of that fear.