I think this is result of tribalism. People chose to divide into two groups on important matter, you can chose to belong to the group by sharing their belief system or not.

Why belief system? We read leaflets listing what are painkillers made from and what side effects might come out from taking them and yet we don't read leaflets when we take vaccinations. I personally don't know a single person who would read the documentation before taking vaccination. Acting like this is basically committing statement of faith.