The author isn't really discussing typography as the main focus, though. He is talking about handwriting, and how it could possibly relate to typography. I'm not trying to be picky or pedantic here; I think the distinction is actually important. He need not be an expert in typography (or even display good sense in presentation around typographic elements) to take a look at his handwriting and find inconsistencies between it and some common metrics used in typography.

One need not even agree with his conclusion/belief that you can make your handwriting better by post-processing it to make it have consistent letter spacing, line heights, etc. I think just the idea of doing those comparisons is interesting, and one is free to draw their own conclusions. Just the idea of making those comparisons made it a worthwhile read to me, because I wouldn't have thought of it on my own. Sure, you can disagree that it was a worthwhile read for you, but that doesn't make it somehow ok to trash the guy's article like the great-grandparent did.

I think what I'm getting at boiled down, is this: be nice. The original author had an idea about something, looked into it, and wrote up some of his findings and opinions. You can disagree with those opinions, or even the methodology around the findings, and it's fine to express that disagreement, but the great-grandparent did so in a fundamentally rude way, which I think is well beneath HN's standards for quality, respectful discourse. It amounted to little more than an ad hominem attack.