That's a good point. No matter how hard any tire is pumped up, there is some combination of riding speed, rider stance/weight distribution, and especially sharp road defect, that will result in a pinch flat. And there is also the matter of different tolerance for risk; a racer going down a windy mountain road faces different risks than a commuter pootling along a suburban artery.

So at some point it becomes an actuarial exercise; do the levees need to be built to withstand a 20-year flood or a 50-year flood?

However, I think the point of the original chart authors stands; most people tend underinflate skinny tires, and overinflate fat tires. (Not to mention, most people choose inappropriately skinny tires for their application, on the illusion it will make them faster). And this information helps to solve that.