FWIW, I also originally read that line to imply "I thought this was obvious, but apparently I need to be explicit anyway".
Given the tone of the rest of the article I assumed that I'd either read something into it that wasn't there or was missing some context - for example, perhaps the person on SO had insisted that this was the correct approach, and you'd gone to some lengths to show that it was not and were exasperated by it by the time you wrote the article.
At any rate - it didn't really take away from your article for me, but I did see it as condescending.
Given the tone of the rest of the article I assumed that I'd either read something into it that wasn't there or was missing some context - for example, perhaps the person on SO had insisted that this was the correct approach, and you'd gone to some lengths to show that it was not and were exasperated by it by the time you wrote the article.
At any rate - it didn't really take away from your article for me, but I did see it as condescending.