Even if he was a fraudster from the beginning, the Oregonians who weren't impressed by the town the Rajneeshees built wouldn't have known that. So the infiltration of the movement into the US would still have been a trial run that revealed the extent of American xenophobia and complacency.

The Rajneeshees should have had the support of American law (freedom of religion), but politics trumped the law, which means the US isn't what it seems, just as Osho's movement wasn't as enlightened as they might have seemed at first.

Arguably, if Osho was always a con artist, you could apply the same skepticism to every religious movement, in which case there's no such thing as spiritual enlightenment.