If we don't, then we're sowing the seeds for discord for when our theories will need to be updated. And it's reasonable to think that they will, as, so far, most (all?) scientific theories has evolved.
IIRC, Darwin's views on evolution require patching e.g. to take into consideration chaotic incidents affecting mortality/genes propagation (e.g. asteroids, epidemics).
Maybe if that theory keeps accumulating patches, it'll end up very different from where it started!
Again, as I've said, it's a reasonable theory. Using the word "theory" isn't about casting doubt, it's purely about intellectual honesty, at least as far as I'm concerned.
The way it's taught is often in an absolute way. The way science is taught in general is in an absolute way. That's because humans struggle immensely with nuance.
Typical traditional Eastern views transcend this creationism/evolution duality for example; one more door to explore.