I think why you see this as religion and not culture is because there is such an intermingling of religion and cultural heritage within the ethnic Jewish populations. But again, you are only making a semantic argument and trying for some reason to claim that certain values come from religion and not culture.
I'm confident that's not it.
Values come from our cultural evolution within groups.
What you are talking about is moral relativism, that morality is defined with respect to the values of a culture. A lot of people reject that notion, saying that there are certain things that are inherently evil, whether or not a given society recognizes them as evil. This idea, of absolute good or evil is not a scientific notion. I'm calling it a religious idea, because it must be accepted on faith, or simply because it "feels right".
To the people I'm talking about, who feel that there is good and evil, whether or not there is any God, the specific patterns of religious practice, whether it's counting beads or sacrificing goats are not absolute moral imperatives, but these traditional frameworks that have developed in specific cultures are a way of focusing an individual's private quest to lead a good life, and sharing that quest with a community.
To put it a different way, there are people who genuinely believe that God commands them to avoid eating pork. There are others who aren't sure whether or not there is a God, but they are certain that there is a good way to live and an evil way to live. Among the latter types, there are people who avoid eating pork, not because they think that God commanded it, and not because they think it is inherently wrong to eat pork, but because it is a system of practice that helps them maintain awareness of the desire to do good. It's about their own awareness, and not anything inherent about eating pork. I know agnostics who keep kosher because it helps remind them that in everything they do, they must maintain an awareness of how they live. The specific practice of keeping kosher comes from a cultural background. For the people I'm describing, there's nothing religious about it. However, they keep the practices of that culture because they think it is important to have a ritual practice, and the one that came from their ancestors is a good as any. The specific practice, then, does not come from a religious belief, but the idea that one ought to have a practice does come from a religious belief.
Are you claiming that fantasy prayer to a being that doesn't exist (ancestor, god, gaia, Buddha, etc) makes one a better person? You'll have to describe a mechanism for that to occur, I'm having a hard time picturing it.
I'm claiming it can. It can focus awareness on a problem. Suppose I am overweight, and I ask Jesus for help in getting thinner. I am so interested in that, that every day I pray a rosary asking Jesus to give me the strength to stay thin. After finishing my rosary, I see a box of Twinkies.
I'm willing to bet that the person who prayed the rosary is less likely to grab the Twinkie, and it doesn't matter if there is a God, and it doesn't even matter whether or not the person believes in God. They just spent an hour using ritual to focus on their desire to stay thin. That will help them say no to the Twinkie, God or no God, faith or no faith.
The same can be true of any activity that you think you ought to avoid. Rituals, such as prayer to non-existent fantasy beings, can help remind you of the way you want to be, and thus help you become that way.
It's interesting you mentioned Buddha in there. He's dead. Every Buddhist knows that. There's no point in any prayer to him or any of the other entities you might be inclined to ask for favors, because they won't hear, but you will. The point of all Buddhist ritual is to focus self awareness. I hesitated to use Buddhism as an example of religious agnostics, because they are very specific about being agnostic. They're all agnostic, at least if they follow Buddha's recorded teachings. I preferred to point out that even in God-believing traditions, you will find a fair number of people who don't think that belief in God is the important part.