Don’t you have your own mind? Why can’t you just mind your own business? Why do you care about what beliefs I entertain?
People’s beliefs are not just beliefs. Beliefs effect how they interpret their experience, and from that determine how they will respond to any given situation. One particular type of action is to elect an official to make collective decisions for us, so it it their job to decide on policies of various sorts, which in turn efect the way the rest of us are allowed to act. So it is that a person’s beliefs don’t just belong to them, since those same beliefs will go on to effect all of us in some fashion or other.
I suspect that it is our political associations that put so much pressure on us to come to a collective agreement with regard to epistemic commitments, about how we go about answering questions, what types of answers are deemed acceptable on some level. So depending on what ways we choose to accept knowledge as authoritative determines political allegiances, and this primarily because we each are individually ill-equipped to handle criticism coming from all sides, and so we tend to seek safety in numbers.
The Spirit of Pragmatism 