Sorry, I couldn’t pass up the irony.
Paul was talking about those who abandoned the preaching of the gospel, not those who left what someone else considers the one true church.
It's not about leaving denominations. It's about leaving the Truth found in God's word.
ANY church or denomination could make that claim about those who left. No one church has a corner on the truth market. That is found in only one place, and that is Scripture in the person of Jesus Christ, not church teaching or denominationalism.
John 14:6 Jesus said to him, “I am the way, and the truth, and the life. No one comes to the Father except through me.
John 17:17 Sanctify them in the truth; your word is truth.
No church or no denomination has claim to that unless they are teaching out of Scripture. Anything else is merely the opinion of man.