In 1867 the Conservatives under Sir John A Macdonald thought it was a great idea in giving Native Indians alcohol in the exchange of land. They were the first Government who started the exploitation. The Introduction to alcohol drinking was the openings of the barn doors as youy know, and then came the sexual abuse, being that a drunken person will agree to almost anything. The sniffing glue was chosen as an alternative to a quick high being that the glue can be bought in hardware stores which made it legal for anyone to walk into a hardware store and purchase glue. I am sure you know that the Native Indian in North America has been robed blind.
A couple of facts obtained by an internet search: Alcohol was used as an exchange for fur, etc as early as 1684 (The Hudson's Bay Company). It wasn't good old John A who introduced booze to the natives. Glue sniffing didn't start showing up until the late 1940s.
I agree that natives got a poor deal from some of the treaties, but the natives went along with them and signed them, so all the blame cannot be placed on the white man. They weren't robbed blind...