As far as i'm concerned there's never any intrinsic offense in a word, the only thing that matters is the context. As far as Darwinist and Evolutionist goes, they're generally meant to be insulting by implication. That is why they're often coupled with words like "dogma" and "religion", with reference to Darwin being the evolutionists god etc.
Remember that the term "big bang" was originally coined as an insulting caricature of the concept, but has since been accepted by most as the common name of the theory. I doubt that will happen with Darwinist or Evolutionist though, due to the connotations of -ist.