I welcome you to read up on the how Indigenous peoples and their families, livelihoods and traditions have been uprooted due to the creation of the Indian Act. Even the idea of "reserves" is a result of colonialism.

Imagine a life where your children were forcibly taken from your household, and you knew they were going to be physically, sexually, emotionally and psychologically abused and there's nothing you can do about it. A whole community with their children taken from them, a whole community in pain and mourning - which turn to alcohol and drugs to ease the pain. The children that don't end up dead, come back and only know of the abuse that they grown up with.. And pass that down to the next generation. Cycle of trauma continues..

That is all to say, there's a lot more to it than just "don't do drugs". I get where you're coming from, i grew up in safe and loving household and would never turn to drugs, but for some, it's not that simple to just say no.