If it's purely cultural and has no connection to reality then it should have "evolevd out" of us. But it hasn't. Being influenced by culture is part of how the system works. The reason you learn disgust is you can't afford to learn by trial and error so you outsource to society.

Now if you think you're a smart ass and decide to "override" the cultural "indoctrination" that makes you find insects disgusting, what do you think is the likelihood that you are the one who is right?

In all likelihood you will find out after some time that you made a huge irreversible mistake.