My opinion is not as fringe as you make it to be. It's true that there are consensus from politicians and the media about what happened but that doesn't necessarily mean it's the truth. In fact, respectable academics are looking at this from scientific point-of-view and coming to the same conclusion.
Here is a UK professor applying probablity theory to understand the weight of the evidence for the alternative explanation in the alleged gas attacks in 2017 and 2013: https://timhayward.wordpress.com/2017/08/31/who-is-responsib...
You are also ignoring the IO that russia is been running which is essentially a carbon copy what they used to run during the cold war, only considerably more amplified and effective these days.
I'm actually frightened by the fact that there are now links here to what is an unquestionably a new breed of academic UIC's now I thought the last of these died shortly after the wall fell.
The parent is pretty much 9/11 inside job conspiracy level stuff. I just stated a few facts about what happened, and how that contradicts the parent's speculation.
Anyway, whatever. Evidently HN is not a forum for reasonable discussion around this topic, because people don't follow what's happening wrt Syria closely.
EDIT: Let's just say, that this reaction is pretty typical. Almost universally, whenever a chemical attack happens and is reported, we're told that rebels are doing it to themselves as a false flag, to inspire western intervention.
After 40th case of rebels successfully throwing canisters with chlorine upon themselves from helicopters they don't have, to inspire intervention that never happened in the last 7 years or didn't bring anything good,... it gets ridiculous...
The problem is that anyone who doesn't watch closely, only sees this one medialized case in MSM, and thinks that false flag somehow may make sense. And "why would Assad use chlorine?" pops up, when it's docummented he uses it regularly.