We are to welcome the weak in faith, encourage the poor in spirit and build up what is broken down.
Is that done in practice, however? Instead, does not our modern Donatist blow at the weak flame, disparage cultural Christianity, and strive to restrict ‘Christian’ more than most ancient Pharisees tried to restrict their faith?
The representative statement ‘If Christ is not Lord of all, He’s not Lord at all’ is, I think, not representative of a robust Christianity. Rather, it is either spiritually naive or a heretical view in the same category as fifth century Donatism. Cultural Christianity is a good thing. Not the only thing, or even the main thing, but a good thing nonetheless if we are to avoid cultural nihilism.
Marcello Pera’s book Why We Should Call Ourselves Christians: The Religious Roots of Free Societies which I nickname ‘Calling Ourselves Christians’ has more on this topic.
Of course, one has to balance this welcoming with not letting the faith get diminished or, as Saint Paul says [Romans 14:1] ‘As for the man who is weak in faith, welcome him, but not for disputes over opinions.’