Here is the reality: Catholic means open and welcoming to all. Not only that, Christ redeemed the world--all are worthy.
Snubbing others if they are not marching in lockstep with you may be an Amish/Mennonite practice, but Jesus gave us a different teaching. Remember the parable of the Prodigal Son? When his youngest son left, the father went out and looked for his return. Jesus told of a good shepherd who, when one of his sheep wanders away, he leaves the other ninety-nine to go in search of the one who wandered off.
I am married to an atheist from an atheist family. My grandfather was an atheist. My favorite uncle and two brothers left the Catholic faith. We all are/remain close. When they feel they need prayers, they come to me. I associate with them happily because we are all children of God, and but for the grace of God, there go I. Grace is not something one keeps solely for him/herself. It's meant to be used, to be shared. With everyone.