Is every public declaration of a sin considered a major sin (kabirah)?

It has been previously explained that smoking in front of people falls under public display (mujaharah), and that one who openly commits a sin is worse in sin than one who does not. Ibn Hajar Al-Haytami explicitly stated that public display is a major sin, citing the Hadith: "All of my Ummah are pardoned except those who commit sins openly." Furthermore, persisting in a minor sin makes it a major sin, even without public display.