"That sin separates some is a sad fact."  That the institutional Church uses sin to separate some is the sad fact.
"it is merciful and loving"  A few centuries back those words were thrown around by the Church while people were burning at the stake - it was "merciful and loving" for their souls, if not their bodies.  It was a disingenuous use of the words then, and it is now, when it is used to justify Catholic exclusivity.