Yes, it exists. I apologize in advance for this, but Muslims do frighten me. I know it's irrational, and this fear does not stop me from treating them with the same respect that I treat any other human being, but every time someone tells me they are Muslim, or they show evidence that they are, a little warning bell goes off in the back of my mind. Was it there before 9/11? No. It wasn't even there immediately after it. It slowly grew as I saw reports and stories about how a trusted neighbor turned out to be a bomber. How a soldier, someone who other people trusted their lives with, gunned down his fellow soldiers. How a stranger walked up and asked two men if they were from the U.S., and when they said yes he shot them. You ask the friends and family of the people who committed these crimes, and they always say the same thing: "We had no idea. He was such a nice guy. He did this, and that, etc." They all seemed like nice people, but they committed unbelievable acts in the name of their faith. That frightens me. And yes, I know every other religion has done this too.
Is it fair? No. Logical? No. Do I know that the vast majority of Muslims are just as kind and loving as everyone else? Yes. Shouldn't I be afraid of everyone else just as much, because anyone could do those things? Yes. Am I? No. Do I believe Muslims are responsible for all the problems everywhere? No. Do I believe they will take over the world? No. But somewhere, in the dark corners of my mind, whenever I think I see a Muslim (whether he or she actually is one or not), my body will be slightly more on guard than it will be around other people.