Mann do not employ robots.Their fund managers are tied to low drawdown contracts, whereas ordinary traders like us are not.Their trading is restricted due to tight drawdowns and risk controls.No comparison.
And on what basis do you know this? They do use robots, or automated trading systems, quote:
"The AHL strategy, with about $21.2 billion under management, uses computer models to make automated trades in more than 150 futures markets worldwide."
The Man Group AHL, automated trade execution system, I suspect is rather a complex beast, covering numerous automated systems across numerous markets (>150). As a "whole" system the drawdown is probably small, but I suspect individual trade execution systems have occasional moderate drawdowns.
ps.I am a senior Software Engineer, so know a thing or two about complex software systems.