If you post a comment that just says somebody said something dumb, you laughed and told them they should stick to $other-thing, and they didn't like it and have since moved, that's a putdown even if you didn't intend it that way. You've actually done this again with your reply: all it tells us is how much more you know than other people, how clueless other people are, and how you've had to spend your life educating them. That may all be true, but a comment like this doesn't teach us anything—it just makes the environment more acidic.

IMO the basic problem is that we all tend to read our own comments as informed by all the information that's in our own head. You have direct access to your knowledge and experience, so for you it's implicitly included in what you posted. No doubt that that makes your comment very rich and meaningful—but it's not the comment the rest of us get to read. We don't have access to any of that—all we have is the information that you explicitly include in your message. That makes for an enormous difference between how your comments appear to yourself vs. to readers.