We hate sin but we do love the person. I was struggling for many years when God set me free. I didn't know that homosexuality was a sin! and when God told me that, He changed me, I did nothing
One day, I had a talk to one gay colleague but I didn't mention to homosexuality, I just witnessed as 4 spiritual laws.
I'm willing to tell everyone about how God saved me from homosexuality but I don't think we need to start with their specific sin, just pray and Holy Spirit will lead the way and let them know how they are before His righteousness.
May God teach us how to tell the truth! Amen.