I think spraying shit on people counts as a chemical and/or biological weapon.
The stuff was pollen that had been processed by a bee's digestive system. The idea that the Soviets harvest bee poop as a weapon is ludicrous. The pollen was also from plants native to that part of Vietnam. So they would have to have this huge factory in the jungle processing bees day and night, then add
T-2 mycotoxin (the purported chemical agent), then put the stuff into canisters and deploy over the same rainforest. BTW, there's no known industrial process for synthesizing T-2 mycotoxin, so you have to cultivate mould on agar jelly plates to get enough of it. The logistics tell you instantly that this is impossible to be true. Knowing the basic details basically makes the Soviet Yellow Rain belief on the same level as Chemtrails or the Fake Moon Landing belief. If you're making a chemical weapon, you just wouldn't use "vietnamese jungle bee poop" as the main component, then combine it with something you need to grow on agar jelly plates! There's simpler stuff you could have made.
Also, the claimed symptoms only match the very lowest level of T-2 mycotoxin exposure (skin rashes, vomiting, diarrhea). The only supposed survivors studied turned out to have fungal skin rashes. High levels of T-2 mycotoxin exposure causes the skin rashes and diarhea, for sure, but also bone marrow degeneration, and necrosis of both muscles and skin, with open bleeding sores all over your body. So the actual substance doesn't just make you drop dead, it makes you look like you've caught ebola or something. If that's the case, there should be photo evidence, which there is not.
The bees did it. Charge the bees with chemical weapons violations xD.