The source of that talking point was a young black protester who wanted real investment into black communities to stop the biggest killer of black Americans: criminals in their own communities. He wanted a structural solution rather than a media circus about an issue (police violence) that is minuscule in comparison to structural racism and would be rotated out of the conversation as soon as the media moved on.
Greenwald's main point seems to be that the conversation about race was used cynically to attack one of his coworkers for completely spurious reasons, and I don't see anything false about that.
If anything, ignoring the cycles of crime and poverty that black Americans are disproportionately victim to in favor of occasional media spectacles is completely on brand for America's dominant right wing neoliberal ideology.
Conservative enough for you?