Nobody even ever heard of Marato. I would like to know how long or how many books he had to page through for Fr. Cekada to find someone who fit his narrative.
This is no "narrative" by Father Cekada. As I said, you're entitled to disagree and basically hold the Cajetan / John of St. Thomas opinion, as Father Chazal does, but you're not entitled to pretend that the Bellarmine opinion is made up by "sedes", some kind of invented narrative. There are many others beside Morato who say the same thing. Part of the problem is, as Decem pointed out, your notion of "Divine Law" is distorted / confused. God never issued a Canon Law. What's meant by divine law is something that proceeds inherently from the way that God has designed the Church, by the very definitions of Catholic ecclesiology. So, when St. Robert states that someone cannot be head of the Church who is not a member, that is considered to be a position from divine law, meaning, from the nature of the Church as constituted by God.