I think his threats and cussing out attacks are what make him different.
I’m the first person I know of who banned him from a facebook group - after he was alarmingly unkind, including the use of profanity, and somewhat threatening toward a poster in my group. He proceeded to try to get other people to leave the group, threatened me personally, and badmouthed the group in other groups until he did enough to get banned from those groups as well. This was before he appeared to be trying to convince people to pay him for clinics, so it wasn’t as public because while he was an a$$hat, he wasn’t trying to make money off everyone while being one. Now that he’s trying to actually get clients with that behavior while just flat out telling lies about everything related to himself, it is more of an issue. I find it laughable he’s now trying to get dressage publications to write articles about him, even.
The reasoning why I would not take a free lesson from him is very similar to yours, except I know I do not trust the judgment of someone with his volatile temper, nor do I want him to know the location of my horses, much less be anywhere near them. Their safety and wellbeing comes first.