I would agree with both Feynman and the person he quoted. An example for me is the internal combustion engine. They're not much to look at on their own, but when I was young I built a see-through plastic model with moving parts. Being able to see the workings in action gave me an appreciation for the beauty in the simplicity of the engineering ( rather than the aesthetics ), and there is no question that in this context, there are well defined scientific principles involved. But that type of appreciation is a different kind of beauty. It's conceptual rather than experiential. It made the engine beautiful in a different way.
Having an art and music background, maybe I can offer something of relevance. What drew me to music was the beauty in the audio experience. Simply listening took me away on an imaginary voyage full of not only sound, but imagery and emotion. It inspired me, and I wanted to be able to do that for other people. However the listening experience is distinctly different than deconstructing and learning how to play the various riffs that produce the sounds. In fact, becoming a musician involves a lot of work and pain. There's not much beauty there. Though that experience does impart a certain appreciation for technical expertise.
After some months of study and practice I was able to listen and recreate and compose, and what happened was that when a new piece came on the radio, instead of asking myself whether or not I liked it, I found myself imaging all the technical details of how it was created and put together, and for some time that gave me some satisfaction, but at the same time, I didn't realize something else was missing. It was only after I set my pursuit of music aside for a couple of years that the beauty of music began to really shine again for me. What had happened is that I had lost the fullness of my appreciation for music by getting saturated with the technical details.
It's very much a left-brain/ right-brain thing. One hemisphere deals with logic and reason, the other with shapes and sounds and so on. The more one is engaged the less the other is involved. If you're not much into music, here's another story that almost anyone can relate to. My other half is a beautician with a lot of experience in the industry, and one day I pointed to a cover model on a fashion magazine and she said, to paraphrase, "I don't want to ruin for you but if I show you, you'll never look a magazine cover the same way again." and she proceeded to point out the flaws in the hair color, a pin showing through in the style, a smudge in the lipstick, and areas where some hasty image editing was done. Poof! Suddenly my analytical left-brain kicked into high gear and the beauty was gone. To this day, whenever I walk past a magazine rack, It takes me practice to set aside the analysis in order to more fully appreciate the beauty.
With a little practise one can learn to switch between the two fairly quickly, which is what artists will often do. Apply some paint here and there, or do some image editing here and there, or try a harmony here or there, and then step back and take in the work on an intuitional level rather than measuring the saturation, contrast, texture, placement, volume, tone, compression etc. Lastly lets not forget that the original context was the claim that, "All truth is rational", and again, we can see that it's not. We all have an irrational side, but elements of that side can still be true.