Can you see why this is worth scoffing at, other than that it’s a tweet from the Republican National Committee?
First, you have to be enough of a douchebag to act like you don’t see that “ending racism” is a process and that a person might have a role in that process even though that role didn’t go so far as to entirely complete the process.
The answer to what she thinks is a rhetorical question is that, of course, is that the idea that racism is a thing of the past that we once had to worry about but no longer have to is a very real and very pernicious feature of American political discourse and practice. And while yes, there are some cases (like the War on (Some Classes of People Who Use Some) Drugs) in which Both Sides in fact Do It, this lie is much more embedded within the Republican Party. The Supreme Court making up extraconstitutional limits on the congressional power to enforce the 15th Amendment because racism just isn’t the issue it used to be is a rather powerful example. And Republicans wanted the green light for a reason: to enact vote suppression measures that aren’t even nominally connected to imaginary “vote fraud” but are solely means of making it more difficult for African-Americans to vote. The embrace of vote suppression is an almost exclusively Republican phenomenon and the RNC’s tweet accurately reflects the ethos.
So there’s perfectly good reason why the RNC’s tweet attracted attention. The idea that racism ended permanently when a few heroic individuals who conservatives can now support decades after the fact in highly sanitized versions — so that the only remaining racism is liberal opposition to racism — is a fundamental principle of the contemporary Republican Party.