I actually think these lists should be called "Falsehoods designers/PO's/etc. believe about x". As a programmer, you may have to neglect these complexities sometimes, even though you know about them and have made the case.
I think some of it too is herd logic. Oh the number of times I've gotten a PM or QA to say "You should validate this field in this particular way..." and the only response to "Why?" is "Because everyone does it that way."