The problem with these conspiracy theories is that they require the US to be the entire planet. For instance, with the Zero Point Energy (which isn't a technology by the way -- it's a physics theory, and not proven) -- OK, you're claiming the American Oil companies are suppressing the technology. So, why hasn't some other country started using the technology? Do you think the US is the only one that would have the technology? Do you think the American Oil companies have the power to control the Chinese government? How about the Iranian government? How about the Russian government? How about some private industry? And how are they going to prevent universities from just publishing anyway? We can't even stop the purveyors of penis enlargers from enlightening us regularly.
The point here is that when you posit a conspiracy theory of some kind, you have to not just explain how they control the knowledge in the US -- you have to explain how they control the knowledge worldwide, when a lot of the countries have no reason to cooperate and every reason not to.