Why do some people feel it's insulting that humans' ancestors crawled out of muck and evolved into greatness?

What I find insulting is that there is no scientific evidence for what you suggest, and, yet, it is being touted as good science. There is scientific evidence for mutation/adaptation/micro-evolution, but there is no scientific evidence (and much science opposed to) the rise of a more complex organism from a less complex state. Evolutionism has been sold as science when it is philosophy. In real science, macro-evolution would be, at best, a hypothesis awaiting testing. No demonstrable, repeatable evidence has ever been found. And, that is necessary for good science to raise a hypothesis to a theory.