Cofty, I know that you think you are quite knowledgeable about Islam-and you might well have a lot of knowledge. HOWEVER, all Muslims do NOT accept Hadith as authoritative. I am one of them. Most are picky and choosy about hadith the way Christians and Jews are about commandments and instructions in the Bible. More so, because they are NOT accepted by Muslims as being "inspired".
OTOH, some very dodgy hadiths are accepted by way too many Muslims. They say they are not athoritative, yet they, in fact, do ascribe them (way too much) authority.
I read a recent account of the reason that so many (muslim and non) folks think that Muslims destroyed the library of alexandria in Egypt. Saladin, a Muslim conquerer, when he was actually destroying a library was criticized by many for doing so. He gave the excuse that one of the righteous Caliphs had destroyed the library of Alexandria, so who were these people to question him? (Destroying knowledge is actually considered pretty heinous in Islam, hence the criticism). Well, he was the ruler and he said it, so it was accepted.
I have since thought on that as being an explanation as to how hadiths(and likely some scriptures in the Bible) gets spread and disseminated. People say things to justify their (questionable/dodgy/controlling/ritualistic/ different/ traditional/cultural, maybe even just plain wrong) actions, ascribe it to or associate it with the prophets/holy ones and suddenly they have a free pass. It gets repeated and, suddenly, everyone wanting to do thus and so has a reason/excuse to do so.
Which is why hadith has the authority of any advice. Good or bad, I accept it or reject it on that basis.