"...it has never been nor is it now acceptable for a communicant to use the reception of Communion as an act of protest."
The Liturgy is not at all "of this world". In the Divine Liturgy of St. John Chrysostomos we chant at the Great Entrance:
"We who mystically represent the Cherubim sing the thrice holy hymn to the life giving Trinity. Let us set aside all the cares of life that we may receive the King of all invisibly escorted by the angelic hosts. Alleluia. Alleluia. Alleluia"
We set aside our earthly cares and concerns, not throw them in each other's faces! What the Rainbow Sash Movement proposes is nothing less than a denial of God's presence in the Liturgy.
Indeed! As the Eucharistic canon of the Didache concludes:
"Let him that is holy, come.
Let him that is not, repent."