If his motivation was to help his roster sure, but that’s not the motivation, the motivation is to get his WR asset on another teams starting lineup to influence the competitive balance of a rival
Apparently the defining characteristic is whether you tell the trade partner your motivation. And that’s kinda irrelevant. You are colluding with the other guy to help him whether he knows about it or not.
Sorry, but no, that is not the defining characteristic.
In the definition of collusion, two teams are working together (colluding) to influence an outcome, and the concern of this is that outcome is
negative.
Example: If you are agreeing that you will lose, or someone else will lose, or how someone's roster is set to help you win (say, not having to face MT who you just traded to that team) those are clearly collusion.
However in every trade made, the desired outcome of both parties in the deal is that they both win games. Because that is their desired outcome regardless of whether they made a trade or not.
In an above board system, everyone is always trying to win games. Can we agree there?
Ok, so back to the hypothetical deal: If I am deep at a position (WR) and trade one to another team because I'm thin at a position he's deep at (TE) and the players are of relatively equal value, that's a good trade. I think anyone would be hard pressed to dispute that. Can we agree there as well?
Now -
if my personal motivation of making this deal happened to be that my targeted trade partner happened to be about to face a division rival, yes - it is in my best interest that they win that game. BUT it is also in my trade partner's best interest to win that game, because as said, we are all trying to win our games regardless.
So look at my motivation for reaching out offering the trade as opportunistic. It is not collusion in any way shape or form, and the only reason you know my motivation for making the deal is because I told you.
To the league it is two teams making a deal where each deals from a strength and gets a player they need. I wanted depth at TE, my opponent needed a starting WR3 because his got the COVID or something. Regardless of whatever motivation I had for offering it, it's an honest, above-board and 100% fair trade.
There's no such thing as collusion without collusion. I basically described "a fair trade" that happened to potentially benefit my playoff chances. Which I'm sure happens more often than you know since teams don't always announce their motivation in offering or accepting trades. But simply because we both want to win doesn't make it collusion, nor would it make it collusion that I want my trade partner to win that week. After a fair trade, we are both starting our best lineups and we are both hoping for the same outcome. That's not at all collusion.