Catholic? whoa. An atheist catholic? (isn't that an oxymoron?) Catholics have a standard for truth - the bible. Catholics believe in objective right and wrong (not subjective). Catholics believe Jesus Christ was the Son of God and arose from the dead on the 3rd Day. What makes you a catholic?
Rationalist? That is the philosophy that man is the measure of all things - you start from man and try to find the unifying answers to our existence (impossible task - can't be done - the best have tried and failed). Without an infinite reference point, rationalism leads to skepticism and finally to despair. The best rationalist thinkers ended up there - Di Vinci, Kant, Hume, Hegel, Nietszche, Sartre.
God is the creator of all things, including the first principles, including love and truth. He is THE standard for all things. He is the potter, you are the clay. Apparently to you, being catholic is a mere association with a building, because you hold absolutely none of the doctrines held by catholicism. Worth is not universal, as we consider people closer to us to be more worthwhile than complete strangers.
You are confusing worth with familiarity. It does not matter if I am close to or love all people. That does not change the fact that people have intrinsic objective value. Your thinking produced such great men as Marquis de Sade, Stalin, Mao, and Pol Pot. If value is subjective, then if I personally feel humans are trash and start slaughtering them, I am right! And Racism is right! Might makes right! You have a bankrupt moral code friend.