Ok, thank you. Now I understand why you said you don't buy into it. Also, I wasn't aware of this 1970s fad, so I think I misspoke a tiny bit by accidentally using the same jargon.
Here's what I think, going back to original question you posed in the OP: ( apologies for the multi-paragraph essay, but, the question "why kids don't want a synagogue in America is a rather large subject. )
Young people don't have a compelling reason to believe in God in the typical Judeo-Christian manner. This being the masculine, aloof, authoritarian, God. However they are tuned in to connection, justice, and truth. To me this is a form of religious/spiritual belief, but it's more akin to recognizing the divine presence ( Shechinah ). In my local area ( urban PNW ), young people are involved in Churches. Young people seem to like it. Synagogue? Not so much. But social action is huge around here among Jewish teens. Kids are involved, want to take charge, and conquer the world's problems. I like to perceive this as a spiritual pursuit because it recognizes that each person's choices have impact that is not easily measured or defined. It's faith. Faith that choices matter, that words matter, that feelings matter.
Being a member of a congregation can be compelling for young people, if it encourages social action, if it highlights an interconnected world, and if it enhances the goodwill and good feelings towards all people. Young people like those things. And they want to participate in those things. But they don't need a congregation to do it, they have friend groups. And they don't need to worship God or be devoted to God in order to accomplish those goals. The divine presence is already close, and I think they can feel that in their friendships, their feeling of interconnection, and their desire for justice.
Beyond this, that a congregation is unneeded, many Jewish congregations seem to be disconnected from the "spirit" of the ritual. And I think young people can see this like a bright blinking neon sign. To me, this authenticity-radar is a good sign. I think it's intuitive, and I define that as spiritual. If the ritual is hollow, why would a young person want to participate. Is it a camp-fire sing along? Yes it feels good to sing traditional melodies in an ancient language among a family and friends. And yes it feels good to be "in the know" and to be knowledgeable about the customs traditions and practices, but all of that is window dressing for young people. It makes the ritual false and foolish. If it's not real, why do it? That's a simple question which I think deserves a compelling answer if young people are expected to participate. In my experience most of the leaders and congregants in American Jewish synagogues aren't able to answer this question in a way that is an invitation for young people to participate.
Perhaps ask yourself, how would the clergy or your fellow congregants answer the question: Why do we say Kaddish? And then ask yourself if the answer is an invitation for a young person to participate or is it discouraging. No matter how I try to answer that question myself, it's not something I would expect to be inviting to a young person in modern America. However, when they see me pouring over texts, or having a heady conversation with another adult about some deep religious/spiritual subject... they want to participate. Why? because it's real. It's role modeling. They see that it's real for me, and my friends, and that is what's compelling. It has to be real.
If a young person comes into a synagogue and sees all the trappings of the ritual but can tell instinctively that the people participating don't actually believe in what they are doing, I say that this is a good thing. It's good for young people to be able to intuit authenticity in the manner that a ritual is executed. And to me it is a sign of spiritual ( possibly not religious ) potential. Spiritual, but not religious? Yes, I'm sorry for using those words again. But hopefully now I've been more clear about what I meant by that originally.
So there's two major factors at play, IMO. 1) Young people don't need an Authoritarian Aloof God, they already acknowledge and interact with the Divine Presence which is close and doesn't require worship or devotion. And this renders communal activities optional or unneeded. 2) If they are part of a congregation, their religious education needs to be from teachers who really believe in God, and really believe in the efficacy of the ritual or else it becomes hollow, and false, and that discourages participation. Both of these, to me, are signs that a young person has spiritual/religious potential, but they don't require a congregation to actualize it.