It’s hard to summarise in a comment but I’ll give it a go. I should also note that this is just my understanding and opinion so I encourage you to seek out more information and formulate your own views where possible.

Neo classical economics is the technical term I guess but you might be more familiar with a similar concept known as neoliberalism. As it’s associated with Reagan and Thatcher it’s also referred to as Reaganomics or Thatcherism. At the heart of neoliberal ideology is free market fundamentalism or the idea that unregulated, profit-motivated, markets are the best way to distribute resources. Doesn’t matter what these resources are (health, food, housing, iPhones etc), neoliberalism tends to see things as products and not human rights. If you’re in America this will sound pretty normal to you, but for us non-americans who have things like universal healthcare, it’s a strange way to distribute a human right.

Another key part is this idea that when rich people get richer it benefits society because wealth trickles down (you may be familiar with the term ‘trickle-down economics’). Therefore economies work best when those with the most capital (the rich) are left alone to do what they do best and government’s role is essentially to facilitate this. There’s a lot more to it than this and encompasses a range of issues.

Why do I think it’s a cult? Because we have all the data now to show that trickle down economics is not a thing, that equality is getting worse, that people are suffering because their human rights are not being met. And yet we are still using this approach. Sure, this is a situation where the powerful don’t want to give up power. But I also think the rich and their servants (governments) do actually on some level believe in the ideology. It’s very much a church of capitalism. The pandemic rely illustrated this on such a visceral level.