Only electric vehicles start at 0 RPM. Normal combustion engines idle under 1,000 RPM and the M5 has a fairly flat torque curve for a naturally aspirated car with somewhere around 260lbs at idle. That's very good and about 50% of its peak torque.

The M5s also have SMG which is a computer controlled manual transmission. No manually operated clutch. Even has a launch mode if you want the computer to control wheel spin for you so you get the best possible launch.

Throttle response is still the wrong metric to use here. And is a bit of a red herring in the discussion.