You are totally ignoring the fact the weight of bikes and bicycle wheels affects the riding experience in ways that rider weight have no effect on. I'm not talking about acceleration or climbing efficiency or anything that would be affected by rider weight as well as bike weight. I am talking about how the bicycle feels when you ride it. If you have never ridden a bike weighing 13 lb or less, you don't have enough information to sensibly comment. And of course, the condition of one's colon will be what it is regardless of the condition of one's bike. The two are not in any way interdependent.

I ride 1,270 g clinchers, and I assure you it is not the same as riding a 2,000 wheelset. The nearly 2 lb difference makes for an amazing change in the feel of the ride, and that is not even counting any minor effects on speed that the lower weight would have. Compound that with similar weight savings throughout the construction of the whole bike, and you really have something special. Try it for yourself before you say it isn't so.