I firmly believe leagues should be commish veto only and in cases like this, where a team has NOT been active or setting lineups and then reappears to make a lop sided trade, it get's shot down, no questions.
If the trade was fair and Owner A was inactive for most of the season, you let it go, and give props to Owner B for getting Owner A off his lazy rear end, but the trade has to be fair.
An inactive owner should not be allowed the same rights as an active owner. How you define "inactive" is questionable, but if he was gone for 2+ weeks, especially in a daily league, I think as commish you have every right to veto the trade.
The fact the owner turned down other, more respectable trades, just adds to the fact the commish had the power to step in.
Don't invite the inactive owner back next year.
Twitter: @dmojr - Always available to talk fantasy or be that second opinion before a trade.