The way this whole thing went down is absurd.

That said, I had an underperforming colleague who never picked up that feedback was negative. They only latched onto the positive statements. This is either a failing of the receiver to hear the negative when also getting positives or a failing of the feedback giver to be direct.

It's impossible to say in this situation, though it caught my attention that she mentioned she was close to closing a deal and lost it last second. If we take the CEOs statement at face value, perhaps she didn't actually meet their metrics.

I can't say if this is justified or not, but what is abundantly obvious to me is 1) their feedback system likely sucks 2) the hit squad was under prepared with the justification for a termination for lack of performance, 3) she called them on their shit justifiably.

I also agree that it should be expected they give a reasonable severance if this is their hiring model... If you by rule whack people.after three months, they should compensate for another three as people were not looking for new work.