Who could sit in Linus' Pumpkin Patch?

It has often been noted that most people who follow a religion, follow the religion of their parents. It has therefore been questioned how legitimate their adherence to, and defense of, said religion could possibly be.

I.e., a baby born in Poland would probably grow up to be Roman Catholic. That same baby, if it chanced to come to earth in Saudi Arabia, would probably be Muslim. In Russia, Orthodox Christian. Israel, Jewish.

If he adhered to his parental faith, he would therefore feel quite comfortable believing in its superiority to all others; and he/she would espouse the logic of the Incarnation, the Quran, Iconography or the Talmud, respectively -- even though his/her outlook appears to be no more than an accident of geography/birth.

Should we then suggest that the only true believer is a convert from some other faith?

What of more secular conceptions?

Patriotism? Politics?

Must we conclude that the only human being who is truly qualified to sit in Linus Van Pelt's Pumpkin Patch of Sincerity, is an emigrant convert/agnostic who has severed all ties (cultural, linguistic, national and religious) to his/her past?