The Plot Thickens
Aha! Update from Jeremy’s comment, which I’m putting here for better visibility. This could be the explanation:
Yeah, Viacom issued a massive takedown notice to YouTube, and a bunch of user-created content got caught in the crossfire. It seems like they just did a rough search on Viacom property names, and compiled the ENTIRE results into their takedown. So there was probably nothing in Spiff’s video that violated YouTube’s ToU, but some comment or tag that referenced a Viacom property to make it show up in the legal team’s search.