Yes, becasue al Qaeda is killing more Muslims than Infidels
There was a recent exchange between what's his name, Zarqawi? and bin Laden on this. If I remember it right, bin Laden issued Z. a warning, and Z. responded defending his actions. Apparently, Z. does not mind killing Muslims if they're shia or sunni, as he considers their denominations not "pure" enough.
Killing 18 Moslem children in order to wound a few US troops makes no sense, and apparently the insanity of it is being realized. I would not make much more of it than this - in other words, US and British troops and civilians are still considered by some to be "fair game".