Of course. I'm not claiming it wasn't a factor, just that it was a very minor factor if any, and a factor directed primarily toward encouraging the Frankish nobility rather than some sort of papal population control. What is irresponsible (and undocumented) is to suggest that Urban believed if the Crusade failed, oh well, at least he had thinned out the knights.
Um, I don't think he specifically looked at it that way, but I do think it was a factor. You can't explain the "Truce of God" and the "Peace of God" (both of which had failed miserably by that time) without it being a factor. Knight violence was CLEARLY an issue on the minds of the Church leaders.