It’s because of their indiscriminate nature.
The US use of napalm on cities in Korea contributed to the nearly 20% of their population that was wiped out.
Not even mentioning the severe lasting impact it had on generations to come. There are still many who are battling birth defects due to the toxins that remained after the napalm attacks.
Not that I’m doubting you, but do you have more info on the lasting toxicity of napalm? I hadn’t heard of this.
I knew that the defoliant Agent Orange had dioxin contamination that led to all those horrible birth defects and cancers. Also, the contaminating nature of depleted uranium is obvious as a heavy metal but I think we still don’t grasp the magnitude of the problem. Iraq and Afghanistan will likely be seeing awful effects in future generations.