Your rebuttal was interesting until this statement. A lot of people don't really understand Keynes, you can tell who they are by their sneers.
A lot of people don't understand Marx either. But it's not a problem because they aren't on the news or in government advising politicians that we should all live in communes. The problem is that Keynesians who don't understand Keynes have a lot of undue influence these days, since misunderstanding Keynes is an easy way to advocate bloated government in a not-yet-totally-discredited way.
A most agreeable comment.