You are so confused....
Separating a family member from the family to avoid the family member from possibly spiritually infecting other family members does not make that family member not a family member.
Once a family member, always a family member.
Similarly, once baptised, always a Catholic. He may become a non-practicing Catholic, a heretic Catholic, or a schismatic Catholic, but he is still a Catholic.
I encourage you to go back to basic Catechism. Our Lord purposely did not make His Church complicated. He wants everyone saved.
It all depends on how you define member, moron.
I (and +Bellarmine and others) define it as: baptized + holds the faith.
If you want to simply define a member as "baptized" then by all means, go ahead. Just realize that's a very BROAD definition, with no distinctions.
According to your definition then, there are 2 possible categories:
a. Member, union with the Church (i.e. holds the faith)
b. Member, not in union (rejects the faith)
Category "b" is what Leo XII is referring to. That's what this WHOLE THREAD IS REFERRING TO.

Members who are not in union with the Church (i.e. heretics).
Why don't you try to understand what other people are saying, before just arguing endlessly?