Why do UNREPENTANT sinners celebrate "Christmas" ?

 Why do unrepentant sinners celebrate "Christmas"?

If they are celebrating the birth of the Son of the 1God, The Son Who is Saviour, Who said to repent , why do they not repent but continue to live according to the 'way of the world'?

What does this say about the "Christmas" festival, which was created by the 'katholika' church of the Roman Empire, under Caesar Constantin?