Had everyone already boarded? It seems like the GA should've op-upped confirmed elites, and given those non-elite standbys the Y seats.

What would have made me furious was if those non-elites were given F seats and you weren't allowed on the plane at all (and I thought that was the direction your story was going)

I personally think it's horrible that non-elite standbys were given F seats. But then again, the GA was probably just trying to get the flight off on time.