You've found a video I've already watched. Good for you?
I never said tanking never happens ever or in what capacity. There are instances of situations like that happening, and you found one of them. How much it actually happens and to the degree it does is what I contest.
It really isn't a serious issue if it is even one at all. The actual cases where you can legitimately make an argument for it happening are few and far between, and one of the things that kills me about these tanking arguments are how people pick an choose what is and isn't tanking based on who's in the draft, whether or not they like the team/consider them rivals, if the team actually gets the coveted player, and a bunch of other irrelevant reasons. It's a highly opinionated discussion more so than it is based in actual fact.
Also, who documented what in relation to Buffalo/Toronto "tanking"? If you mean fans and the media went crazy those years towards both teams then yes, that did happen. No one from the NHL front offices, those teams, or anyone of legitimate importance "documented" or acknowledged anything in that regard.