Please note the second word of this summary is "often".
If you want to know why its "often" and not "always" visit your nearest library and take a look at the size of books on the subject.
And here lies the problem with the internet today and the comment boards such as these. People will actually walk away reading these kind of 2 minute summaries thinking they know something about the subject at hand. And on top of that you can get yourself a great rep "educating" and "informing" the public without ever actually "educating" and "informing" the public.
If you want to know why its "often" and not "always" visit your nearest library and take a look at the size of books on the subject.
And here lies the problem with the internet today and the comment boards such as these. People will actually walk away reading these kind of 2 minute summaries thinking they know something about the subject at hand. And on top of that you can get yourself a great rep "educating" and "informing" the public without ever actually "educating" and "informing" the public.