He could issue a statement that politicians who are publicly pro-abortion are not to receive communion, and if that still doesn’t work he could publicly name the politicians he is referring to.
I’m equally sure they have not been. If they have been told anything, eucharistic ministers have been directed not to withhold communion to those politicians since that is the stated policy of the archbishop.
I haven’t seen anyone claim that a Protestant can receive communion but regardless of who might have said this the fact remains that they cannot, though why we should expect the archbishop to enforce this rule is not clear … given that Protestants are no more a part of his diocese than senators or congressmen.
Ender