Chemical warfare has been categorically banned by the majority of nation states since the conclusion of World War I as a particularly reprehensible means of conducting warfare.
A couple reasons for this. As some have so blithely commented dead is dead and the end result is the same. The difference lies in the abject pain and suffering that results from chemical weapons. A short description on the mechanism and effects of Sarin which was used in the Syrian urban center of Ghouta
Chemical nerve agents: A "very toxic and horrible way to die" - CBS News
Chemical weapons are indiscriminate, shifting with the prevailing winds and sinking into bomb shelters and basements where innocents take refuge. They have little practicality winning conventional battles. What they are very very good at is killing a large number of clustered people indiscriminately. Or in other words they excel at targeting urban centers. That is their inherent purpose and threat in the modern world.
And given this threat there has been a precious precedent established since the Geneva Protocol, that nation states do not use these weapons in their conflicts. There have been numerous bloody wars between merciless governments and militant group and aside from a couple of notable exceptions they have all abided by these norms. When Bashar Al Assad uses these weapons without any serious response from the international community it erodes this precedent. It encourages or resolves totalitarian regimes that there is no significant threat from using such large scale weapons of mass destruction. Progress comes one step at a time and only an oblivious fool would be the one to to go back on this global precedent of condemning the use of these weapons.
That's why it is important to create a global condemnation of these weapons, to monitor their stockpiles and use, and to take definitive action in the event of their use.
I only speak to let you know I find these types of theatrics you are pulling disgusting. It is my firm belief that it takes a man who is offensive to the core to create a spectacle of the suffering you are talking about. It takes a degree of obliviousness and lack of empathy to slap on a "what's so bad about it". Have some shame.