I want to downvote you but I'll reply instead: I've noticed this sort of response on HN more lately, where someone is criticized for the way they did a thing, or their approach in solving a problem, but the criticism is completely unhelpful.
patio11 clearly said in his blog post that CSS wasn't his bailiwick. Instead of simply saying, "You did it wrong!", you might say:
Let's not be excessively gentle here: text-indent -1000 is a terrible hack (try input type="img" instead) and while I'm not mean enough to think the author deserved what he got, I also don't think we should feel overly sorry for him learning about how HTML works the hard way.
If you've been at it for a few (and I do mean "a few") years, building sites that work in all major browsers (FF, IE 6 - 8, well, alright, Safari) turns out to be not the most difficult thing in the world.
To add to this: The reason the text-indent trick is used was normally for header replacement, navigation replacement, et cetera, and was a method of providing strong naming that didn't clutter markup and fed screen readers or CSS disabled browsers.
Also to expand on it a little more, I use(ed) this trick a lot, and I've never had the image shifted off the page. I'd be interested to see the HTML that actually broke.
I didn't mean to comment directly to the author but make a general statement of the current state of the art in CSS: to achieve an effect use the craziest hacks one can find. As you said, patio probably just found that code on the web and used it.
patio11 clearly said in his blog post that CSS wasn't his bailiwick. Instead of simply saying, "You did it wrong!", you might say:
Here's a link to some popular CSS image replacement techniques: http://css-tricks.com/css-image-replacement/
It's also worth pointing out that, in that article, patio11's text-indent hack is cited as probably the most-commonly-used method.