The stumper question asked was: Why can’t some websites host PDFs?
Well, after asking Google, no direct answer was found is but I came across enough information to lead me to this conclusion.
Look at it this way,
A PDF is formated with text. A document that you would type up on Microsoft Office Word (for example) is also formatted with text. Now, refer to Facebook. The majority of us have a Facebook page and understand that we cannot directly upload our english essay to share with our friends. We would have to screen shot the essay which would convert it to an image in the format of jpg. Because the purpose of Facebook is not to share documents to one another, the creators of the website set it up in a way where it isn’t compatible with the PDF format.
You can check out this Facebook conversation between concerned users to read more if interested. LINK