I have inadvertently, I think, confused the picture on RADALT u/s - certainly the 'collar' was in force, but the 'old' MEL required
"Approach Minimums or operating
procedures do not require its use"
and this obviously did not 'flag up' the trap that awaited, since detailed knowledge of the role of RADALT 1 is required to see that coming. In that respect I reckon Boeing were 'at fault' as they did not differentiate between RADALT 1 and 2 failure except in the effect on GPWS, and certainly an OPS note about the effect on the A/T 'RETARD' would not have gone amiss.
However, as we know the No 1 RADALT was not 'U/S' and therefore not MEL'd, so this is actually incidental to the accident which was primarily caused by 3 pairs of eyes looking the wrong way.