“What should I say when someone morally offends me?”
When you set out to correct people, one of several things may
happen: (1) they reject your advice and never think about it again; (2) they
reject your advice now, but take it to heart later when they have time to
reflect; (3) they accept your correction politely, but only in order to
get you to stop talking and go away; or (4) they accept your correction
politely and actually learn from it.
It also happens occasionally that your intended target rejects
your advice, but other people come to know of it and benefit from it. That
is not the ideal outcome, but it is still a pretty good one.