It wasnt vetoed. It was reversed by the person the owners placed in charge of the league.
As I said in my reply you quoted, I wouldve been fine with it either way. The reason I am also fine with him reversing it is I understand that trying to keep the atmosphere of the league fun as well as competitive is important.
We had an owner in one of my redraft leagues the other day who meant to drop Cin Def, accidentally dropped Gio. He realized what he did, messaged the commish, explained what had happened. During this time, I had put in a bid on Gio and was going to be awarded him. The commish fixed the issue, and re added gio to his roster and dropped the intended player.
I was fine with it. In your world, I assume you would say "too bad". Well it was his mistake, but things happen and the commish used their discretion and decided it wasnt some tactic, and it should be rectified. Thats his job, imo. Similar to what happened in the OP.