People don't like their belief systems challenged. It's the same reason many wars are started over religion or ideology. And due to cognitive dissonance and confirmation bias, it will not stop until/unless humans evolve. You could censor it, but the censorship would also be subject to the censor's cognitive dissonance and confirmation bias.
If it bothers you why don't you just ignore those posts.
If it bothers you why don't you just ignore those posts.