Although that is one of my favorite quotes, it's being misinterpreted here. In a competitive/race/training situation where you are pushing yourself as hard as possible, that "as hard as possible" is always going to hurt. However, as your fitness rises, you can more easily climb at a lower percentage of that "as hard as possible" if you so choose. Increased fitness really gives you the option to make the hill go easier or go faster in a casual/recreational riding situation.
+1
in the fall base period I was climbing pretty much any hill at sub-threshold. It requires some low-cadence work, but generally painless.