I had a discussion with a well-known science writer some years back who was very interested in Buddhism. The way it had been presented to him was as a kind of ethical humanism .
But then he took the time to actually study the teachings and found them replete with kamma, rebirth, devas, hell realms.
It didn't fit with his worldview, and he saw no reason to change his view so he rejected Buddhism and moved on. It's an honest approach.