IN +CHRISTO REGE.
I just dont see what is so important about this.
You do not join with those who dont believe what you believe.
These people are fixated with false unity, unity for the sakemof unity. Its syncretistic and unionistic and not the unity Christ wants believers to have.
This isn’t about sharing communions. Protestants don’t believe in it - their communion is just a quick snack, nothing more. Catholics actually believe in the presence of Christ in the Eucharist, and hence not something non-Catholics are supposed to receive. Protestant bread, who cares if whoever takes it, it means nothing.