Just opining that it ought to be is not any violation of law. It’s the same thing that keeps Freepers from being arrested for saying that, e.g., all liberals should be hanged.
Carrying it out is the violation.
However, “disparate impact” which has been a successful liberal complaint in the court, might be very interested if combined with the genocide statute. Hey, you’re killing off black people at a greater per capita rate than white people. You’re genociding.
Liberals aren’t an ethnic group.