Nobody was selling emdrives (to my knowledge). It was more of a "Hey, this is a weird effect" and an effort to explain it. That's less snake oil and more science. Most of the time there is some explanation that doesn't break your framework. Sometimes there's a breakthrough as you figure out the new thing. Sometimes you can't figure it out.
Shawyer absolutely was soliciting investment. Anyone with a basic physics education could see his proposed mechanism was utter nonsense, so it's hard to be charitable towards his rather hyperbolic marketing.
