I think there definitely is a mental struggle for most, that a few molecules can become self-replicating, then lead to actual life. For the most imaginative among us, that's a stretch, so I can understand it having opponents.
We're also very self-centered as a species, even arrogant about it at times. I blame even religion for this, because even the bible says god created us in his image and gave us dominion over the other species. Well, how lovely and convenient that all turned out to be.
Let's face it, we can't fess' up to the notion that we came up out of the primordial ooze with the rest of the things we share the planet with. It might not be pretty, but the truth is the truth. Science, as it's been so well put, is after the truth, and not just what makes us feel good.