You can draw attention to the issue without impugning the character of the person in the way. Even saying "that's not true" is better, since it doesn't unambiguously assign a negative motive.
Of course it would have been better to say it differently; that doesn't make what he said instead a justification for what happened, or that it would have changed anything.
Also, by that point his fate had probably been decided, and he might as well make his point and confront them. Perhaps they'll feel guilty; or perhaps others present will remember to push back more a little earlier.
