There's an essential note which is not quite clear from the article too: while encryption algorithms are reversible, most hashes are not -- sometimes we forget, but they're soft of by definition many-to-one (injective) functions -- while encryption is fully reversible (albeit mathematically "hard"). Of course, this won't matter for websites that use the same hashing algorithm, but it's an essential part of why it doesn't make sense to encrypt rather than hash passwords apart from key compromising.
Yeah, secure hashes are (hopefully) not mathematically reversible - but when you can try 350 billion combinations per second on a GPU cracking setup, that stops being such a great defense. This is why you have to use a slow hashing function.
