Okay, and the person who replied was clearly talking about private planes. Hence the “so simple” part. Unless you interpret it uncharitably, like the person who replied to you said.
Notice, it's a very common occurrence. People note that something posted is inaccurate, in their own personal interpretation. It's usually not directed at them, but there's a need to correct the posted because of their personal interpretation (re: xkcd Duty Calls). This is not to say, I've never been guilty of this (maybe this post is a great example). Sometimes I want to argue. Sometimes I want to explore my own beliefs, given another person's position, and get it recorded somewhere. That being said, I can recognize that it's not constructive for the conversation at hand and I'm trying to do better, while still growing my own understanding.