No, cynics have a very valid point: humans could not have evolved from natural selection alone in the timeframe they did. And many evolutionists simply can't handle the truth. The evolutionary pressure that drove human evolution, while leaving the evolution of other animals untouched, is tribal warfare. Many academians cannot accept that modern humans are violent war makers by nature any more than cynics can accept natural selection caused intelligent humans to pop out of the background so fast. Until scientists do the math and discover that humans are fundamentally nasty creatures and that eglatarian socialism could never work, the theory of human evolution is flawed.
Six million years is plenty of time for humans to differentiate themselves from the closest related species, chimpanzees, by 2% in genetic DNA and 6% in genomic DNA. The observed rate of mutation is both necessary and sufficient to effect this amount of change over six million years.