In some leagues, like mine, a trade requires a considerable amount of work and negotiation to get the other party to see it as a win-win and accept the trade. So yeah, to have others in the league just veto it for no clear reason? You owe an explanation to the people who wasted their time and effort.
Also, you should only consider what has happened up to the point where the trade was accepted, not yesterday's stats. If one half of the trade took a season ending injury, that's still not grounds for a veto. That's just too bad.
12 team H2H league, standard scoring, no PPR.
QB: Cutler, Kitna
RB: All Day AP, CJ2K, F.Jax, R.Brown, S. Greene, Dixon
WR: G. Jennings, Roy Williams, M. Williams (sea)
TE: J. Tamme
K: Hartley, Carpenter