I think a key problem here, even more than in most "race-related" stories, is the amount of misinformation there was in the media. People were already outraged by what they thought happened, and couldn't reset once they found out what did happen.

I only touched on it briefly, but there were reports claiming that Rittenhouse was a police officer, numerous outlets claiming that he shot black people, the false reports that his mother drove him to Kenosha were traced back to an Instagram post by some random celebrity. The only way to get a reliable picture of what happened was to watch the trial and/or double and triple check sources. The vast majority of people weren't ever going to do either.

As for the Waukesha case, I honestly don't think the media is sitting on it because Brooks Jr. is black. There's just not much drama in it. If it's true that he was running from another crime, and that it wasn't a terrorist attack, there's not really anything juicy to get people stirred up about. There was a huge flurry of news about it when it first happened because it seemed so obviously to be a deliberate terror attack, but once that narrative didn't really pan out, there wasn't much else to say.