I expect you were downvoted because your post isn't particularly interesting, and won't lead to thoughful discussion, let alone thoughtful discussion about the article in question. Sure, someone who doesn't know the difference between "its" and "it's" might learn something, but, while I'm not going to go so far as to say "that's not what HN is for", it's... well, kinda not what HN is for.

Another -- unfair -- reason is that some posts about grammar and spelling come off has holier-than-thou nitpicking. I don't believe that describes your particular post, but it's hard to convey tone/purpose in text, and people get annoyed by stuff like that.

I didn't downvote you (at 21 hours later, it doesn't matter at this point), but if your post was "in the way" of scrolling to more interesting conversations, I probably would have. I come to the comments on articles because I'm curious about what people are saying about the content of the article (and was thrilled in this case to find that a commenter here was actually the person who built the software that ran this bar). As much as I do believe that language and clarity is important, I don't particularly care if someone mistyped an apostrophe into the article's title. It's just noise to me.