This post shows how hard it was for scientists to prove it's bollocks. And the above comment shows how the general population doesn't want their hopes dashed.
It really was clear at the time. Even then people pointed out that the measurements didn't behave in the way you'd expect if it actually worked (e.g. thrust didn't correlate with power).
There were plenty of people saying "But imagine if it did work! We could get to other stars in a few years!" but you always get crazy optimists that ignore all the evidence with stuff like this (c.f. solar roadways).
This post shows how hard it was for scientists to prove it's bollocks. And the above comment shows how the general population doesn't want their hopes dashed.