That's very true. Speaking for United Methodists, we practice open communion, meaning everyone at worship is invited to partake, member or not. The church proclaims that the table of Holy Communion is open to anyone who seeks to respond to God's love and seeks to lead a new life of peace and love.
With the Catholic Church, communion is, in part, a restricted Club kind-of-deal. An important part of communion for them is embracing the notion they're all tightly bound together on the same team. A Catholic congregation that allows a non-Catholic to partake in communion is committing a huge no-no because that act would amount to essentially "saying one thing while doing another."