I didn't think you were, and didn't mean to imply that I did.
It's just that it's pretty hard to be sure of the exact chain-of-evidence of any file you download off the Internet.
There is no way of telling how many intermediate owners that file had, and how many edits they may have made, for whatever purpose.
My guess is that the Islamofascists themselves decided the original raw video was too bloody for their purposes, which was merely to recruit more Islamofascist crazies.
They may have dimly realized, in the fashion of primitive animals, that one or two Americans might get really riled up when they saw all the blood, so they cut and restaged some of it to sanitize it a bit, just as you say.
Like maybe editing some faux pas, like dropping the knife, shouting something Un-Islamic, or something along those lines?