Why must leadership be the only source of irrational action?
The command and control situation on the ground is hardly perfect.
The revenge motif runs deep in Arab culture and there has certainly been enough violence to produce deep reservoirs of it on both sides. It is just as possible that this act (the chemical weapon attack) was organized and carried out by a subordinate Syrian commander with access to the weapons; one who did not care about anything except getting revenge for the death of (fill in the blank).
It might be the truth that neither the Syrian or Russian leadership had anything to do with the ordering the attack except...for the maintaining of the research, production, and storage facilities that make such attacks possible. And surprise! That, and only that, is what got attacked by the western powers late last week.
Kill to your heart’s bitter content; but not with these weapons.