It was a cause but it wasn't the reason. The reason was a menacing pucnhing power of Bell. McClellan is a scary good choice for ATBMP but head-to-head it turned out he was stopped, not Benn.
The Ring Magazines rankings - 100 best punchers of all time. #7 Julian Jackson #27 Gerald McClellan #91 Nigel Benn Something to think about
That doesn't bear a great deal of weight when considering punching power. Firstly, it is widely agreed that G-man went into the Benn fight as 'damaged goods'. Many suggest that the damage was done by Julian Jackson. Secondly, what knocks one person out might not knock out another. Just because Benn withstood G-mans punches, and Benn's effectively stopped G-man, doesn't necessarily mean that Benn hits harder. It could be said that punch resistance, punch accumulation and even the fighters physical condition were the more defining factors in that fight. As for who was the hardest puncher at 160lb, in my lifetime it is Julian Jackson without question.
Jackson was natural as a 154 pounder, while McClellan fit 168 perfectly. Something else to think about. Not to mention that list, as with every single Ring list ever compiled, has repetitive glaring inconsistencies.
McClellan was never a full-fledged SMW b/c he messed up with his coach (I consider McClellan as the best fighter Steward really built up into a superb fighter, right after Hearns) and was more of a MW than a SMW when he faced Benn... Also, McClellan had something called accuracy which Jackson lacked a lot of times (can you spell blind?), though he knocked his opponents unconscious...