You're both wrong and I'm right:

http://edition.cnn.com/2013/08/27/wo...ine/index.html

"Modern weaponry, while it's grown more lethal, has also grown more precise," says Michael Rubin, a former Pentagon official now with the American Enterprise Institute. But chemical agents disperse to affect large numbers of people and "can produce horror for a lifetime."

Some conventional attacks do the same, he acknowledges.

But there's another reason that it makes sense to view a chemical attack as a reason for international intervention, Rubin says.

"We want to establish the parameters of warfare. If you don't, combatants will keep pressing the boundaries. Ultimately, the question is, should we have any boundaries in war or not?"

It's a slippery slope, he says. If a chemical weapons attack goes unchecked, what about some other form of weapon of mass destruction -- a biological or nuclear attack?
[...]
Tierney, in The Atlantic, suggests a "strategic self-interest" for the United States to oppose chemical weapons.

"Powerful countries like the United States cultivate a taboo against using WMD partly because they have a vast advantage in conventional arms," he writes. "... Washington can defeat most enemy states in a few days -- unless the adversary uses WMD to level the playing field."

Rubin rejects that argument, saying the U.S. advantage in weapons of mass destruction precludes any possibility of a level playing field.
https://theweek.com/articles/460452/...tional-weapons

Daryl Kimball, executive director of the Arms Control Association, told Mother Jones that he found no reason why those restrictions should be lifted or ignored:

Holding the line against further chemical weapons use is in the interests of the United States and international security, because chemical weapons produce horrible, indiscriminate effects, especially against civilians, and because the erosion of the taboo against chemical weapons can lead to further, more significant use of these or other mass destruction weapons in the future. [Mother Jones]

While sarin gas might actually kill you faster than, say, bleeding out from a bullet wound, it has become a "weapon of terror" that we are "hard-wired" to fear because of how unexpectedly and quickly it begins to work, Charles Blair, a senior fellow at the Federation of American Scientists, told the National Post.

"They couldn't smell it, see it coming and 'wham,' next thing you know they're in convulsions, frothing at the mouth and they're dead," he said.