There was no "gas attack". Some murderous slaving ISIS criminals took a sledgehammer up on the roof, knocked out some holes, and shoved some empty canisters into them. Then they mixed some bleach with some muriatic acid and left the scene. Later, there was of course some chlorine residue. But simple physics proved that full canisters of poison gas hadn't been "dropped out of helicopters": the roof wouldn't have stopped so many of them. [1] Actual gas bombs of the sort that USA sold to Saddam for use against Iran are carefully constructed devices that can actually be dropped from aircraft and expected to distribute poison gas. Dropping bare storage cylinders only works in the movies. The real conspiracy theory is that the internationally-recognized government of Syria had anything to do with those attacks. They had neither means nor motive. The "moderate rebels" (really ISIS) that USA had been supporting had both.
Of course you don't care about details. Even your pose of criticism of Saudi is cynical. You want to sell the Saudis bombs to kill Yemeni children right up until they don't want to buy them anymore, at which time you'll want to start bombing KSA. Mostly you just support status quo USA policy for the last 70 years. That is, we kill lots of brown and black people so that the public can be buffaloed into giving armaments manufacturers obscene amounts of money. The public would prefer to spend that money on literally anything else; you disagree. You'll probably make a show of declaring that you're actually more against war than I am, but your religious devotion to every lie that the war media has ever tossed off shows where your heart is. Pacifists oppose killing innocents, both through sanctions and through the wars for which sanctions are pretexts. The Middle East is broken for the same reason that Latin America is broken and Southeast Asia was broken for a long time: USA broke it. The best thing we can do for them is the best thing we could have done for them in the 1950s: stop interfering with their governments, stop providing armaments to various parties, and stop killing them.
[0] https://cepr.net/images/stories/reports/venezuela-sanctions-...
[1] https://thegrayzone.com/2019/05/25/opcw-syria-gas-attack-sta...