Its not all black and white when someone will break something it happens or doesn't happen at any ungiven moment.
I have seen plenty of new things break too that supposed to be the cats meow.
As far as rear ends go, as long as the bearing pre-load is good and the bearings are good i wouldn't loose much sleep over a rear end.
On the other side of the coin when running a manual transmission and dumping the clutch at 5000 RPM, you will find the week points of a driveline.