Question

why evolution should not be equated with progress

Answer 1

In fact, there is no real 'progress' in the idea of evolution. Evolution is simply the generation of diversity and the shaping of the diversity by environmental factors. The only progressive trend in evolution seems to be that more and more complex body designs have emerged over time. However, again it is not as if older designs are inefficient! So many of the older and simpler designs still survive [..] In other words, human beings are not the pinnacle of evolution, but simply yet another species in the teeming spectrum of life.