Ugh, that really sucks. I'm sorry to hear! Sounds a lot like what someone I know got for their feedback too post group exercise. In that case, he strongly felt the group was making a mistake, but didn't manage to persuade them politically, so he went along with the group think and then for the feedback call, said all the rest of the performance was all great, it was just that one aspect of the group exercise that was wrong.
There's no winning in that case and you just take the bad luck of having gotten stuck with a bad group.
At the very least, I hope that girl didn't get an offer either!