Neither of those trades is vetoable IMO, even though they're both pretty stupid on the surface in their own rights. Both owners can easily claim they are trying to improve their teams with the deals, and I highly doubt there's any collusion (provable or otherwise).
Blount and the Bucs are a mess, but there's matchup-based upside there, and Rivers is a mess in his own right. The McFadden deal is arguably more fair in the short term - DMC is a stud, but he has a terrible schedule and Bush breathing down his neck to add to his checkered injury history, and a positive argument for Bennet's output based on recent history makes it a lot closer than you think.
I'd way rather have DMC and Rivers, but there's also nothing to veto IMO