It's already a while ago since I flew the A320 (which is in deed a very good aircraft!). But regardless of the type of aircraft:
They crashed because the crew was unable to fly the plane raw data...
Basically its very simple: If not really needed, do not reset a computer via CB in flight, especially when a failure continues to reoccur. They easily could have continued with this problem to Singapore. It's a short flight only, or divert if you don't feel comfortable. No big deal...
Bad luck paired with a bad decision, paired with bad flying skills (training...) = crash