Personally I'd be suspicious of the views of someone who has apparently managed to bust 3 AMPs...
I own, and have ridden, the B4 bonded carbon, bonded aluminium and older welded versions...they all work fine for me.
but then I'm 72kg, and ride my bikes smoothly, treat them like a rigid, try not to get too much air and never forget that they are 20+yr old, 22Lbs full suspension aluminium thoroughbreds.
It's always really difficult to sequence a failure like this without it on your hand. Maybe a failure of the RH chainstay tube?. ..and of course he was probably 'just riding along' when it happened.
-The seatstay to dropout joints look good.
-Seatstay bridge is still in place.
-RH chainstay to BB is unclear.
-LH chainstay to BB is good
-RH chainstay to dropout is in place.
-LH chainstay to dropout has de-bonded.
-The shaft on the rear end of the Risse shock seems to have sheared.
I have also seen a report of one failure of these bonded B4s at the hole in the chainstay horseshoe yoke cut for the Mercedes carbon fibre kickstand.
They'd made the bonded forks for years, but maybe AMP were not too familiar with the risks of carbon/aluminium bonds when they upgraded their bonded Alu rear end to carbon for Mercedes?
Plenty more reported failures of Manitou, Marin, Pace, Klein, Cannondale and Nishiki frames out there, and people are still riding those.
All the best,