I think the thing is that there is no official accepted value of LD50 for THC since there has never been a recorded death from THC:
> The median lethal dose (LD50) of THC has been determined in various animal species through oral administration and ranges from 800 to 9000 mg/kg. In humans, there have been no recorded instances of fatal overdoses resulting from acute THC use. However, estimates for a potentially lethal human dose range from 4 to 15 g.
> The median lethal dose (LD50) of THC has been determined in various animal species through oral administration and ranges from 800 to 9000 mg/kg. In humans, there have been no recorded instances of fatal overdoses resulting from acute THC use. However, estimates for a potentially lethal human dose range from 4 to 15 g.
https://www.ncbi.nlm.nih.gov/books/NBK563174/