So prior to you going in the store, the entire Apple staff never noticed that over half of their displays had defective screens? That's what I'm saying about perception, until you pointed out the defect, no one else noticed it. One person sees defect, but another misses it, but when you point it out...bam, then it becomes noticeable.
I agree with you that we pay for "perfect", and I hope you find one that is perfect to YOUR perception, just saying that in my opinion if you are satisfied with your screen then it's not a good idea to post a pic online and ask others if it's fine, someone will find a flaw, and then it becomes difficult not to notice said flaw.
QA has certain guidelines that they follow, does every screen have to be perfect...nope. Just has to fall under the set guidelines.