A common law citizen trope which is no doubt in the final analysis completely bogus is that social security was modelled after mandated insurance for ships. David Siegel in another question suggested that it might have actually been insurance for railroad workers although I wonder if it wasn't more modelled from private pension schemes. Anyway is there any kernel of truth?
I kind of suppose that their interest in the topic more derives from the fact that it represents something that the government takes out of your every paycheck which it is thus widely satisfying and appealing to have a conspiracy theory-like explanation of.