You've wedded yourself to the term non-sensical, which isn't going to help your position. Whatever tryout period that you've decided would have been sufficient for the Mets to conduct while they are trying to win a division would never bring Vientos, Baty, or any other prospect to the point that the Mets would come away with a projection that they would be making the right decision with the prospect that would be more reliable than years of performance by a proven major leaguer. In other words, it wouldn't have meant enough. Now, that doesn't mean that the proven major leaguer would be the better choice, or the other way around. But it's reasonable management, and nowhere close to nonsensical. If Ruf were hitting his career average against lefties, instead of struggling some in a whopping 26 at bats, this wouldn't even be a conversation.
For some of us it is non-sensical. If you don't feel the same way not my problem as we're all here to express our own feelings about the team and their decisions.
It still would be a conversation considering they gave up a bit too much for a 37 yr old platoon bat when they have one waiting in AAA for free.