The answer is fairly simple: The MSDN reference is not authoritative. It tells you how Microsoft's compiler behaves, and yes, it usually happens to coincide with what the standard says. But when someone asks how the C++ language deals with some situation, only one text has any authority: the ISO standard.
So when answering questions about C++, people tend to reference the standard.
If you ask specifically about how MSVC implements it, then MSDN would be a perfectly valid source. But most questions are simply about C++.
Or to put it another way: if MSDN contains a typo, then MSDN is wrong. If the ISO standard contains a typo, then that's how the language is defined.