It was in fact a joke, but with some truth. You're making serious claims about a vast body of literature and methodologies without having actually understood their entirety. This is exactly what you're criticizing social scientists for doing: drawing conclusions based on observations from systems no one has fully isolated for experimentation. If you think this is methodologically unsound, that's fine, but you shouldn't then do it yourself.

I was making the pointed armchair observation that all hypothesis being tested in the social sciences are false. Of course none of the down voters seemed to noticed that my hypothesis is a social science hypothesis. Subtly is lost on HN most of the time.

More seriously the social sciences do have a lot of problems, some driven by the methodologies used, some by ideology, and some by the inherent noisiness and unreliability of the data available. Not an easy area to do science in.