192mg/kg is on the higher end of estimates, which do range widely because they are based on animal studies. However, it's not comically large. Do the math, and it comes to just over 14 grams for a 75 kg (165 lb) adult. That's more than most people would ever consume in a day, but it's far less than the 600 gram lethal dose of alcohol for that same person. Alcohol kills far more people because it takes 100 - 250 grams of alcohol for a 75 kg adult to get drunk, so the lethal dose of alcohol is only about 5X the intoxicating dose vs. 100X the intoxicating dose for THC.

It depends on your weight and how much tolerance you have, but a fatal does could be as little as 2 grams (2000mg) of THC, which is about 100X what it takes to get high. Since marijuana is about 20% THC, and you only actually absorb about half of that when you smoke or injest it, the minimum lethal dose is probably about 20 grams, though some people may be able to tolerate a few times that amount. Fatal marijuana overdoses are rare, about 200 per year in the U.S., but they do happen. Claims that you can injest your body weight are based on articles written by advocates who can't do basic math.