Contamination with carbon from more recent sources (i.e. carried in ground water) can make material appear younger to carbon dating. It seems that your "proof" that fossils are young is based on the false assumption that this cannot happen.
According to your post 45 (this thread) Noah's Flood was 5000 years ago. Based on that post, the Pleistocene extinction would have occupied the second to fourth thousand-year "days" of Creation.
How then does the dating of the Pleistocene extinctions help your case in any way ?