One of the most compelling proofs, I think, is the fact that Trump has never denied it. If you're the president, and some unknown entity is building up a huge following by claiming to speak for you, you'd want to make it very clear that you have nothing to do with it. Even if you like what they're saying now, you might not like it later...
He forgot "so I can virtue signal on social media."
"No, I don't have any data or reasoning to back me up, but I heard all the cool kids are doing it."
"Those you are taught to trust the most..."
Congratulations - you've done more for black lives than BLM has.
894: "When we’re done he’ll claim Kenyan citizenship as a way to escape." https://qanon.pub/?#894