It is because the payoffs would be so enormous that business like this and "overunity motors" continue to gain attention. All of those other elixirs were shams, but this one will work! Finally, immortality! The enormity of the reward causes the payout matrix to lead people astray.
Don't get me wrong, I see a vacuum chamber, which is light years ahead of most of these enterprises, but I would not spend a dime on it until it has been proven to work in a region of space relatively far from the Earth's magnetic field.
That said, Woodward does not seem to be an actual charlatan, so I don't have a problem with funding him. At least he might turn up something fun and/or interesting, even if I don't think it's going to usher in a new space age.
I personally believe he rides that line of charlatanism where he's not pursuing this theory in bad faith at all, but he of course recognizes that tromping around on the edge of a theoretical branch that most physicists don't think is worth exploring garners attention he wouldn't otherwise receive.
I strongly suspect that whether history remembers him as a charlatan will depend heavily on whether one of the supports of his branch proves false and it snaps off, or whether he's been right this whole time and we suddenly oops ourselves a propellantless drive that operates by coupling to the gravitational field and pushing distant objects around. ;)
Propellant-less propulsion within the confines of Earth's magnetic field or gravity well is still pretty valuable. The entire space economy at the moment is Earth satellites, all of which are constrained by propellant.
Being able to build boxes that are bigger on the inside than on the outside would also be very valuable - like a standard 40ft shipping container that fits in your pocket.
And that's very close to the kind of thing we're talking about here.
Don't get me wrong, I see a vacuum chamber, which is light years ahead of most of these enterprises, but I would not spend a dime on it until it has been proven to work in a region of space relatively far from the Earth's magnetic field.