The point is if you're that fucking fat, you're benching what... 1.5x your body weight if that?
This dude is pulling 4.5x his bodyweight. That's impressive. Has nothing to do with body fat %. Some of the strongest men in the world are 20%+, but when they're pulling 1000 pounds then it becomes impressive.
I'd agree with you if a dude could get a 400lbs bench by just being fat. Is a 200lbs person benching 400lbs more impressive than a 300lbs person doing it? Of course. But if you take a fatty who never lifted a day in his life, they're a long way away from benching 400lbs.