That post is not a flame. It isn't even close in my opinion. It is an example of a simple, direct criticism of what merlyn saw as a fault. Sure, he could have put it a bit more nicely, but it's hardly required. If his post had been as a response to a comment of mine I wouldn't have viewed it negatively at all.

You're going to run into far, far worse flames (if you haven't many times already). Take the positive from each comment, drop the negative. Not everything has to be sugar-coated.