Back in college, there was this thing called the "4, 4, 40 challenge" where one would have to drink 4 liters of water, in 4 minutes and hold it down for 40 secs. Lots of vomiting would ensue.
More than 1200 mg of pure THC, or 1200mg of cannabis leaves?
Those aren't even remotely the same thing, in the same way that 12oz of beer and 12oz of everclear are very different, or 1g of pure nicotine is very different than 1g of tobacco leaves.
Not to mention, LD50 is about a single dose. There's a big difference between taking one shot an hour for 16 hours straight, and chugging 16 shots in one go.
Looking at the wikipedia page for some of those, it seems to be intravenously.
For example, Botox (the last one): “A toxin is 1.3–2.1 ng/kg intravenously or intramuscularly, 10–13 ng/kg when inhaled, or 1000 ng/kg when taken by mouth”