The thing about "cultural Christianity" is that when people do describe it, all the things they describe rely on certain things being done by other people. Not on the absence of other religions. So of course if you send your children to Sunday School they will grow up with that experience. If you don't, they won't. But Sunday School also relies on other people running it. And all the other things described:
- Visiting Church fetes - requires volunteers running those fetes
- Church weddings and funerals. Requires the vicar but also requires the upkeep of the church for those events
-Christmas/Easter - the same
-Carol services. Huge amount of work behind the scenes- regular practicing, parents taking their children to practice
Etc etc. None of those things rely on their not being Muslims. But when some people talk about protecting "cultural Christianity" they don't mean by volunteering at church.
Eg. You have Kemi Badenoch who describes herself as a "cultural Christian" saying
A typical Liberal Democrat will be somebody who is good at fixing their church roof and – you know – people in the community like them
This is meant to be an insult!
And then later she talks about how she is a"cultural Christian" from growing up in Nigeria where people are very religious. But she is also sort of quite disparaging about those people themselves. She gives the impression she thinks she's cleverer than them.
Like I said earlier, there is a kind of superiority from these kinds of people, which is far worse than from a straight up atheist. They rely completely on people who either believe strongly in Christianity or at least are prepared to put the hours in "fixing the church roof"/organising choirs but they want to feel superior to them and they don't seem to want to acknowledge their reliance on them. Instead there is a nagging sense that as church attendance drops they might lose the things they like. But they want to blame Muslims/immigrants for that gradual change in culture. It feels quite dog in a manger. Muslims by and large are not stopping people bringing up their children as Christians or attending church or maintaining church buildings.
There's nothing wrong with being a cultural Christian. But it is a passive position (which is also fine) not everyone needs to be involved in everything. You don't need to believe in Christianity or actively participate to enjoy being part of a culturally Christian country. I think if you want to claim that that passive position is under threat though, then you can't also mock those that fix church roofs etc. And you can't blame immigrants.
It's the same for other stuff too. If noone volunteers for cricket, village cricket will die. If noone shops at the high street the high street will die. The last government smashed funding for libraries so many are only kept open by volunteers. Who are constantly disparaged for being middle class/woke. Neither of those things are true.
It's like me not bothering to change the oil I my car and then, when it breaks down, blaming my neighbour for washing his car every weekend.