Trump on Syria: Bombs can never be a humanitarian response to war crimes

THE international outrage caused by the chemical attack on Khan Sheikhun in Idlib province last week which killed over 80 people, most likely carried out by the Syrian regime, is justified and understandable as are calls that something must be done to end the horrific six year war in Syria.
The use of internationally banned chemical weapons against civilian targets is rightly and widely condemned but why does their definition not include such equally awful weapons as depleted uranium and white phosphorous or even 'conventional' weapons like the MOAB bomb dropped on Afghanistan just this week?