If he is saying what I think it is, then snakeoil is a term that was used roughly a hundred or so years ago. It pertains to "serums" that "docs" would sell making them sound like some new fangled product to save the world. Basically, I think he is saying that they are talking them up to a much higher standard than they should.
Thanks for clarifying
The plugs may be very good. Just don't seem to give the performance boost expected.