We already knew he was super racist. He had already said and done an entire litany of things that were obviously anti-black/brown.
The media's "sudden realization" that he's a white supremacist is an attempt to move the bar for correctly identifying someone as racist into cartoon villain territory.
His systemic attacks on PoC weren't enough for media outlets to peg him as racist, his bigoted speech wasn't enough either. Only his laughably extreme monologuing was enough.