That's a peculiar thing to say! I'm not a Roman Catholic myself, but I'm quite sure that the Roman Catholic Church has the books of the OT in their canon as authoritative divinely inspired scripture.
Furthermore, it is peculiar to only except the Gospels, when the Gospels and also the rest of the NT literature, cite the OT as authoritative all the time.
I'm also quite sure all christians - be they catholic, orthodox or protestant - affirm the rejection of Marcion in the early church, precisely because he tried to get rid of the OT. Marcion even had to falsify the few NT books he accepted to cut out all references to the OT.
I don't think you can blaim a parent for what their child does wrong. I mean, a parent might carry some blaim, but in the end the child is responsible for what he does, not his parents. If a man is a sociopath, maybe his parents failed, but in the end it's he himself who chooses what he does. The parents might even have done everything perfectly and still the child might be for whatever reasons be compelled and choose to do something horrible.
Similarly, I don't think anybody can blaim God for the evil he himself does. God has given men a free choice. The possibility of rejecting God is inherent to that freedom. The capability of doubting his existence isn't something God directly created, but it's something inherent to human freedom. I don't feel I'm a chess piece in Gods hands at all, because he has given me a freedom to choice whatever I want. Of course he does hold me responsible for whatever I freely chose. With freedom comes a responsibility. I can't blaim the devil or God for the sins I have comitted, I have only myself to blaim.
For me, it's in a naturalistic world that I'd feel a chess piece. But a chess piece moved by mindless natural processes, instead of by a Person. If everything in the world is governed solely by naturalistic processes, I don't see much room for basic human freedom of choice at all. It's all just chemical processes in the brain and psychological constructions; no free choice. It's not the childs fault, but his parents failed. But is it then the parents fault, or is the grandparents fault for failing? In the end, there would be no fault along this line of reasoning, just mindless chemical processes in the brain.......
That'd be worse than being a chess piece if you ask me. At least the chess piece is moved for some purpose by the chess player.
For me, religion doesn't feel like some comfort for death or something, but more for purposelessness. So, to be honest, you're absolutely right I couldn't find solace in doing worthy deeds during this life in a naturalistic world at all. I wouldn't see the point. I'm sure I'd still be inclined to be friendly towards the people around me or something, because of basic human moral intuition, but I wouldn't even know why I'd be doing it. It seems to be - and I guess I'm reasoning more or less intuitively here - that there has to be some purpose to existence before deeds get any worth. In a modern atheistic naturalistic worldview, I guess there is no purpose to the universe or to human existence, it just happens because of mindless natural processes. I don't see in what way I could ascribe purpose and worth to my deeds, when my existence and the existence of the world around me is purposeless.
For me, it is only in God that I find purpose and meaning and therefore a motivation to strife to do worthy deeds in this life. The prospect of communion with God which I can enjoy now partly, but fully in the eschaton, is what motivates me everyday. It is the promise of forgiveness and redemption through the work of his Son that gives me hope to continue to strife in faith towards that goal, for which I believe God has created me, though I don't deserve it at all. It's what gives purpose and meaning and worth to the deeds that I do here.
I guess I just admitted I'm a coward by your standards, huh?