Despite what Catholics are "obliged" to do or believe, they don't.  But Catholics believe in a great deal of what they have been taught and what they learned by living, by experience.  That is why many stay a part of the Catholic Church,  because it does feed their souls in a way that they are not fed elsewhere.  That does not mean they believe everything "the holy Catholic Church believes, teaches and proclaims..."  Do you really believe they do?

The faith journey is not ended upon profession of the Catholic faith.  Catholicism gives it a direction and a focus, which is our Lord.  It has important teachings on God and the message of love of neighbor that Jesus taught. But it does not know it all.  Knowledge is still growing.  It is ridiculous to think that they got it all right in the first 300 years after Christ, or finished up all they had to understand in the next 500, or the next 500.  The problem with Catholicism is its absolutism in an evolving species in an evolving universe.