i really don't think we witnessed the same thing, i think anyone in the same situation that the Wiz team would have been pissed off. The rest is just them making conclusions based on what they were able to understand. Yeah Wiz DJ was maybe too vocal about it but i don't see how Wiz was unprofessional considering the situation, at least he performed even with these last minute changes and no one for the vocals
Wiz wrote that Taeyeon backed out without actually checking what was up. It's a dick move.
DJ changed his story multiple times and it was easy to see he was lying saying stuff like "We found out only 10 minutes before we were going on stage" even though he tweeted about it an hour before.
The cancellation wasn't their fault and they handled the performance well, but we still have a right to be pissed about the drama they caused over their false assumptions when they could've just talked it out with the people involved.