I believe that you're engaging in semantics. As many other people have patiently pointed out in the threads here, racism is not a manner of scale. It's a type of attitude and belief system that can manifest in many ways. I'll just supply you with the links I provided to someone else below:
I suggest that you do some reading. There are plenty of resources both online and offline to learn about unpacking and examining white privilege and unconscious/conscious racist attitudes. Starkey's Links for Clueless White People is a good way to start. Coffeeandink over on LJ also has a ton of links and resources. You can read every single thing that was written during RaceFail '09 over on LJ; rydra_wong on LJ keeps massive linkspam posts under her "gcadod" tag.
What NOT to do, such as outright dismissing any claims of racism in Parker's end product because it doesn't indicate clearly that there's a pervasive attitude towards Arabs in Parker's work? This is a good way to start: Derailing for Dummies. What you're doing, whether you mean to or not, is derailing and denying that there's a possibility of racism/bigotry manifest in Parker's end product here.
If I see a depiction of a hook-nosed Jew carrying money bags, dressed all in black, and carrying a cup of Christ's blood, and that image is not a satirical commentary on a trope or insidious anti-Semitism, I will call that image racist. To deny that such an image alone is racist is absurd.