Having grown up Protestant, long litany of denomination my mom ran us through: Presbyterian, Methodist, Disciples of Christ, and UCC the one thing all those Churches had in common was open communion. No matter who you are, what your faith as long as you desired to know Jesus you were welcome at the table. See I can still recite it. You were also free to believe what you wanted about communion. My mom(serial denominationist, closet Catholic) taught me about the real presence. I was very surprised to find out no one else believed this when I was 11 or 12. For most Protestants, open communion is about acceptance. It is welcoming and evangelical to share communion. Thus, to be excluded from Catholic Communion when they so freely share theirs, no matter a personās beliefs is difficult for many to understand. I am not speaking for all Protestant denominations, just the ones I attended as a child.