One thing I find interesting is that it's so toxic to children but not adults. Humans are relatively large animals and can take a lot of toxins. Otherwise most of us would be dead. I found this interesting:
In other countries, neem oil has been used on cats for flea control. Some adverse reactions have been reported. Symptoms include feeling sluggish, excessive salivation, impaired movement, trembling, twitching, and convulsions. Some of the cats died. However, most of them recovered within 1 to 5 days.
My cat had a nasty growth on his forehead. My grandma put some neem oil on it and it healed up after a couple weeks. She believed it was the neem oil but I don't believe it was. The reason it wouldn't heal, he kept scratching off the scab and making it worse. The neem is bitter, one taste of it on his paws cured him of scratching at it. Gives an idea for curing bad pet habits.
The problem here is a lack of research. There needs to be studies into cannabis and neem oil considering how common it is. Otherwise all the talk for and against it is interesting but not enough science behind it. As an earlier poster stated I'd love to see stats on what % of the population is allergic. Once again it shows how little regulation really goes into insecticides, not so much that I'm worrying about the Neem (but of course I am), but all the other nasty shit they approve.
As for the argument that it's in our foodstuff but we don't get sick. I do get sick, no idea if it's from neem oil. Once a month, give or take a few months, sometimes several times a month. I'll get a horrible migraine headache and lay in bed puking my guts out for a day or two. Feel like my brain is pushing against my skull. I'm not the only person I know who suffers from this affliction. I doubt it's from neem oil but it's one of the dozens of possibilities and we don't know how common Neem allergies are.
One thing I found annoying when I was looking for information on Neem Oil. There's anti-pseudo science websites out there that trash fake medicine. I checked a couple out they were saying this woman peddling skin care products had contaminated her stuff with a INSECTICIDE! Commonly used on fruits and vegetables. Guess what it was.
There was another dentist guy saying he could keep your teeth from rotting with a magical ingredient. Once again the pseudo-science de-bunker was horrified to learn an INSECTICIDE was involved. If he'd done his research he would have known that neem oil has been used on skin and teeth for thousands of years and it's relatively safe.
There's also lots of websites saying Neem oil is perfectly safe for children and babies. That the toxic amount is huge and there's no way a baby could eat that much of their product. This one says their diluted mixture is good for pregnant women as well. Some of their links site rubbing neem oil mixes on teething babies gums.
I looked into baby toxicity studies and 5 ml, a teaspoon, is enough to poison a baby. Crazy.
I'll stick to what I said earlier. I'd use the stuff for a small period of time in Veg, if I needed it. I wouldn't ever use the stuff in flowering and I wouldn't give it to my plants as a preventative, dousing them with it to keep them from getting a problem.
I know growers love preventative spraying but it's a bad idea for another reason. Insects, microbes, or whatever get resistant if constantly exposed to a substance. I'm sure it's a matter of time before we get neem resistant insects as much as the agricultural industry uses is.