To pull a stunt at a time that would seem to be counter productive can be used to give plausible deniability. Calculating devious megalomaniacs like Assad and Putin would see that at the front of their handbooks.
What if I told you the attack on Syria was ordered by Putin to keep his Manchurian candidate's cover plausible?
This attacked was totally unnecessary. Syria has no chemical weapons. John says so. A question for my leftist friends. By todays standards wasn't John colluding with Russians here?