I commented this here for this precise reason. `Libtard` is definitely a word people on the internet use but the other one ive literally never seen before. Someone went out of their way to add one and not the other. I agree though that, ehem, rightoids are supremely sensitive tho.
Just in time for America's ongoing discovery that "liberal" and "conservative" are in fact quite similar ideologies. New insults are called for. I propose "progtard" and "reactard".