When I was growing up, I knew a guy who was a member of the John Birch Society.  He went to the same church as my family did, his kids to the same school as my siblings and I did.  One of his kids was my classmate. The guy was a weekly communicant, active in the parish, in the community, in various charities and in local politics.  By all accounts, a pillar of the church and of the community.
And he was a vicious, relentless, raving, flaming, roaring, soaring bigot.