@RetiredF4:
Looks like that post came in the middle of one of my self-imposed "sanity breaks", and I must have skimmed over it when I came back. Apologies for missing it, as I said.
@_Phoenix_:
If you look, the "Low Speed Stability" basically does what your proposed "line of code" suggests, except it pitches the aircraft down rather than moving the THS directly (which makes sense given that the autotrim follows pitch commands). Now, as RF4 states, it appears that Alternate 2B loses all but the load factor protections due to the rejection of all three ADRs (a double failure will keep High Speed Stability) - looking at the Flight Law table I linked to earlier, it does not seem to preclude the stability protections from returning after a time, it may just be that there was not enough time in which the airspeed data came back to do so in this case.
This seemed odd to me at first, but having thought about it for a bit I'm guessing that the design team considered an inappropriate automatic pitch down in the event of all 3 ADRs agreeing on bad data more of a risk than eliminating the low speed stability protection entirely. Again, this makes sense if you bear in mind that they'd assume the pilots to be making appropriate inputs, and not consistently pitching the aircraft up into and beyond the stall regime.
@jcj - The pilots didn't get "lost" in the modes, they simply never properly assessed the situation or came up with a solution. For whatever reason, the PF seemed to have become fixated on pulling the nose up - going as far as to hit the sidestick priority button several times (and thus shutting out the PNF), and at the same time told neither the PNF nor the Captain what he was doing and why.
The only time flight laws ever came up on the CVR was the PNF's call of "Alternate Law" at the start of the sequence.