It is not ALT2 in itself that causes the loss of low speed stability and the uninhibited travel of the THS. It is only the loss of 2 or more ADRs that causes this specific condition. It is possible to be in ALT2 with a THS that behaves as in ALT1.
To say that no pilot would trim nose-up while pulling is a bit presumptious i think. I do not find it inconceivable at all that the PF would have trimmed nose-up, perhaps even to the same extent the autotrim did, if he had the means to do so. He was after all back to mechanical stop on the stick for a full 30 seconds.
Not much a what he did was the way to do it, but he did it nonetheless.