Bull puckey. The only evolutionary bottleneck recorded in our genes happened about ~70,000 years ago when our species was reduced to about 2,000 individuals, not eight.
The only conclusion one can draw is, if the Flood did occur it was only a localized event and affected only a small segment of the population.
You place your trust in a different set of information than do I. I do not consider the fossil record to be a localized event, but stark evidence of a global deulge resulting in global death (with the exception of some who were saved).