The very fact such a celebrity endorsed the photos gave them credibility with believers for decades. Frankly, a lot of intelligent and well known people were part of the Spiritualist movement and used their statuses to legitimize it. Some of them had scientific backgrounds. Much of their evidence looks (and frankly is) ridiculous by today’s standards. But we shouldn’t fool ourselves into believing we are smarter than them.
When people are the targets of manipulative word usage, it is not just a bruised ego at play: their neurobiology shifts. Cortisol levels increase with stress, for instance. If people feel defeated by the incessant abusive language out in the public sphere, their testosterone levels decrease. The prefrontal cortex becomes overwhelmed.