Why does the Church keep the worst sinners at a distance by denying them Communion?

The Church doesn’t hold the worst sinners at arm’s distance: The sinners themselves do. The Church isn’t forcing them to sin. They are doing that quite on their own. The Church does not withhold the Lord’s compassion any more than he did. But he was only compassionate with those who were repentant, and then he warned them not to engage in such activity again. When you were waiting for an annulment, you could have received Holy Communion if you were not having marital relations with someone with whom you were not validly married. Perhaps you didn’t know that to do so is a grave sin. One cannot profess one’s unconditional love for the Lord while at the same time engaging in sinful activity. The Church wasn’t holding you at arm’s distance. You could have gone to confession and determined to live as brother and sister until you were validly married—and then received Holy Communion. Many do. Unfortunately, priests often fail to tell people this.