All mountain bikes will do what you want but they are not meant/built for full on DH; i.e big drops and jumps.
I also very much disagree. Point of a all mountain bike is that it’s a mountain bike, it’s capable of mountain biking, ie trips to the shop, trail centres, xc rides, DH, freeride, big mountain riding.
The rider will be giving up a lot of the time before the bike.
My big bike is a 160mm “all mountain bike”, i wouldn’t really question using it anywhere. I’m hitting 25ft+ gaps, 10ft+ drops on it, without ever thinking the bike is beyond its comfort zone. The same goes for any DH track i’ve ridden (alps, llangollen and many others).
I think that the problem is how they’re marketed. A serious amount of DHers i know, once the penny dropped how capable a 160mm bike is, have got 160 bikes and the DH bike gathers dust.