But using marijuana? That was a step too far.
Originally called "Rocky Mountain Moongrass", this obvious weed substitute was supposed to be in the game (and offer you an increased hit chance for a white), but as long as it was there, the Australian Classification Board refused to grant it a rating, on the grounds that it would refuse to classify any games that:
"depict, express or otherwise deal with matters of sex, drug misuse or addiction, crime, cruelty, violence or revolting or abhorrent phenomena in such a way that they offend against the standards of morality, decency and propriety generally accepted by reasonable adults to the extent that they should not be classified."
So, the folks at inExile decided that it would just be easier to remove it from the game entirely. That's a reasonable choice: one consumable in a game with dozens you'll never use will hardly make or break the experience.
...But it is worth noting that other drugs, one of which is clearly a stand-in for heroin, managed to slip through and stay in the game. Heck, you even spend an early mission helping a druggy get to his stash, which he's clearly addicted to. So. That's weird.
...Just don't tell Australia about it.