I'm sympathetic to what you suggest, but news coverage shouldn't be based on whether or not the subject being covered deserves attention. It should be based (though I will be the first to admit that the media often misses the mark) on the public interest. That's a more complex conversation.

The public does have the right to know about large assemblies of racist organizations, and not reporting on them would, it seems to me, reflect problematic editorial judgment if not outright censorship. I don't know the answer, but I don't think it's keeping the public in the dark.

Picking and choosing what the press is allowed to report is one of the marks of a totalitarian regime. Freedom of the press is guaranteed by the Constitution for a reason. Unfortunately, the abuse and excess of that freedom is part of the price we have to pay in order to remain a free society.