There has never been a ruling by the UN, ICC, ICJ or whatever about the use of agent orange breaching the Geneva conventions or being a war crime. All legal analysis is post hoc. Today it might be, but it's irrelevant to this foreign agitators ridiculous claims.
You assert they knew based on nothing but a hope and a dream. Chemical warnings are designed to prevent misuse, and I would love to hear you claim the warnings on the box were "will cause generational harm". In fact it's the exact opposite because soldiers were incredibly ignorant of the toxicity of the chemical, a fact veteran advocacy groups have spoken of at length.
They also stopped using agent orange shortly after more information came out about those kinds of harmful effects in 1969, which goes against your claim.
If you think any of this is convincing of the claim "America and ISIS are the same" you've got your head in the sand.
This was only a cover story however.
