We can only guess what really happened. There are a number of possible scenarios. Allegations of this type are sometimes raised by disgruntled employees who concoct such allegations knowing a company will give them a termination payout just to get rid of them. It is easy money. Insurance companies also do this in some disputed claims, which are more bother to defend against than just settle and be done with them. A settlement in these instances proves nothing.
Herman Cain can’t possibly defend himself against this.
I believe his best response is, “under the terms of the settlement, I am not allow to respond.” This is a non-win situation.
If his wife Gloria wants to, she probably can respond. And I’ll bet you she says something to the effect that “I stand by my husband.”