Right, it's basically an extra line in the sand drawn by creationists in order to make up for losing part of the argument. Then they assume creationist theory is still at least as valid as evolution theory despite this handicapped standard.
The same thing happens when scientists estimate the age of the universe due to the position and velocity of stars we see. Young-Earth theorists like to claim that because we can't actually go back in time and witness the timeline of the universe first-hand, science has no argument - despite the fact that the observations made about the cosmos are entirely physically consistent with phenomena observed here on earth. It's hilarious.