There is no general means of inferring a history of population sizes from a current population size. Attempting to do so coupled with the claim that such attempts disprove evolution shows both ignorance and hubris. I will add a fifth point, really a corollary to the first point. The SciCre argument is self-contained, and deliberately ignores all other sources of information. Human history does not record a global flood.
Human history is continuous through the times proposed for a global flood.
Geological evidence shows no sign of a global flood. Fossil evidence indicates that mankind is far more ancient than SciCre'ists would admit. None of this evidence goes away or is addressed by the population argument. In short, the SciCre population argument fails on many different criteria. Honest creationists should eschew its use.