Trust me! Right wingers perfectly understand what they're claiming not to understand. They want to sit with and come up with excuses for dismissing Black lives (not only do they not care about Black lives, they never cared), and so they come up with reasons to argue against the phrase.

They know exactly what it means.

They just don't like it when Black people declare their humanity. Their entire self esteem as "white" rests on having a permanent pariah class they can look down on in order to feel better about their own mediocrity.