I suppose there's this possible defense:
In poker you have to lose a hand, and some chips, once in a while. If you act as a ratchet -- chips in but never out -- you'll get no action when you do hit a hand because the table realizes you're a tight-ass just folding until you get the mortal nuts. And when you finally get a hand you'll win only the blinds.
So maybe the Walman trade, and this blockbuster, were Yzerman's Crazy Ivans. He didn't assign any value to these two players because he figured both would soon be bumped off the roster by young guys so he just tossed them away seemingly carelessly. Other GMs see this and think "Stevie's back on the wacky weed, let's see if we can get some free assets too."
The problem with this defense though is: Poker is a game of imperfect information and in hockey other GMs know as much about the cards you hold as you do; so the Crazy Ivan doesn't really do much for you.