I do not think it should be easy to say that it is a human limitation. I can tell from the history of my post that I posted here that at first I managed to get through BA Round with many FFYLs. And as a result of my constant efforts, now I can easily clear it.
Regardless of how many FFYLs you experience once you are able to finish the BA Round with No Moxxi conditions, I think that the level above is possible.
But, I think it would be very difficult to come up with the ability to clear for the first time under that condition.
And after mastering the arena I visited other places with the invitation of somebody(NAT_ZERO_SIX). At that time, I thought the No moxxi build was not possible on the battlefield where many bullets fly. But, now I can see my judgment about the limitation was wrong.