They don't really give a shit whether we're stupid or not. They know they can say whatever, the media won't question it, Twitter would either say it's inconclusive if he was hacked, or just outright lie and make up some bullshit vague answer that nobody has time to pursue at this point.

If the private organization running something as important as the US Presidential debates had any integrity, they would simply say because we can't verify at this time the authenticity of the tweet, it has created a conflict of interest and we will replace the moderator. No big deal. But that probably won't be the case because stupid pieces of shit happen to be in charge of way too much in this country.