Hi,
JD-EE
"what caused it to enter that stall condition?"
Only two causes are possible
1 The pilots made error
2 A defect of the plane
This is debated from ages on this forum
So far .. after reading the BEA preliminary reports and the note (and taken not in account all the speculations and technical stuff posted on this forum) .. the answer (until proved false) is item
1
All between
1 and
2 is armchair stuff
Like it or not ... but that's the life...