Why would anyone not like PDF

Because, while I agree that PDF is a great tool for the things it is good at, people use it on the web for things that it wasn't designed for and isn't good at.

It's so frustrating when you are browsing a pefectly good website and then you suddenly get thrown into a large PDF document containing a couple of paragraphs of text and some pointless graphics (with the text appearing two pages in because the first two pages are flashy corporate logos and [censored]). All because someone in the marketing department couldn't be bothered to take the two paragraphs of text out of their Quark prepared product spec brochure and put it directly into an HTML file.

Still, at least it's better than a Word document being used for the same thing...