Those who are seeking a salvation in some other way than Christ alone don't realize that's what they are doing. Self righteousness is the most deceitful sin there is. They think their attempts to be accepted with God by what they do are works that are blessed by God Himself but they have no clue they are under a curse, as the Scriptures put it. The gospel of free and sovereign grace is the only thing that can cure them but they resist it, all the while they strive and work to be accepted and bark at those who are not as "holy" as they are. Many around them know it and can see it but you can spend the rest of your life presenting all the evidence of their false way, but guess what - blind people really cannot see. It's true. God must do a work to give repentance of their hatred of grace alone before they see a need and fit the Biblical definition of a sinner who needs mercy. It's called total depravity, this state they are in. They are void of a righteousness that God requires and they go about at attempts to produce it themselves. They don't know any better. If you really say you love people in that mess you will always give the the offense of the cross that gives them no wiggle- room to boast in their fleshly efforts in what that call salvation.