Reading the text is made difficult by the spacing used. The paragraph headings for instance just look like bold text and could be spaced better to allow them to be found in the page. The ragged right edge is too ragged and makes the text difficult to read.
If it wasn't ragged, it would most likely look even worse than that Pooh example in the article. It depends on the size of font, which you can't (on the web) control. And he is right, justified paragraphs without hyphenation are ugly, unless you have a lot of characters on a line. Which he has not (around the images especially), and the example is even worse. I wouldn't even think of displaying justified paragraphs for lines shorter than, say… 80 characters or with hyphenations [1]. But even printed newspapers give up justification in narrow columns and has ragged right.
[1] I think that you could make it in javascript. With too few characters on a line, display paragraphs ragged, with more, justified. Maybe someone already did it.
Really? I am not aware of a way to do this (other than just making the line longer relative to the font size, which statistically makes the breaks more even)
Web browsers do text justification horribly. Beyond not hyphenating words, they also don't change the spacing inside the word. (I want to say this is kerning, but I can't determine if that applies to adjustable space, or only to the static space.) Until web browser can handle that, there's no reason to justify text on a webpage.