The plastic rot we are all experiencing is clearly a manufacturing defect. Honda neglected to add UV blockers to most of our plastic external parts, and this rot is the result. The thing that is really irritating about this is that it is completely unnecessary. If Honda had spent a few cents more, all these parts could have been made from polyvinylidene fluoride (PVDF) and been tough as hell and almost completely impervious to UV. PVDF is used as the outer coating on golf balls, for example.
I say this is a clearly a manufacturing defect, and I think the photos below prove my contention. Some of the plastic parts obviously did have UV protection. Look, for example, at the difference between the plastic dash and the plastic glove-box covers. Or the difference between the side panels and the pannier material behind the painted covers. This bike is my daily commuting bike, and I ride it every day, so it does get a lot of exposure . . . but I do think that the exposure is at least roughly the same for the entire bike. If the differential rot between pieces is not a manufacturing defect, then why the difference?