I'm part of the "childlress" class you describe, and no, it's overtly obvious how much work a child is, and is the precise reason I don't have any.
> Having children is a good thing for the soul.
I get the same fulfillment (without all the work) by being extremely close with cousins and siblings with children. It's really fun and fulfilling being the "cool uncle" - but having one of my own 24/7? No thanks, hard pass!
It really isn't. My sister lived with me on and off during her kid's first years and I saw a lot of it (also experienced the joys of being the cool uncle). But I still underestimated the amount of work you have to put in. Also: taking care of a 9-month old is possibly 81 times the work of taking care of a newborn. But evolution is funny like this: the payoff scales very close to the energy expenditure.
It's really hard to explain the benefits one gets from having kids because, well, with your mentality one doesn't get any benefits. I was almost militantly "child-free" until something I can't quite explain happened to me, and put the world in an entirely different perspective. This is when we decided to try for a baby. We were different people already when the baby came.
The differences in thinking between parents and the childless might well be larger than political, racial, ideological, religious etc. differences.
If you want to focus in particular on the notion of how “selfless” you learn to be after becoming a parent — this form of “selflessness” is actually just an expansion of selfishness to include your own children. It isn’t some enlightened ego free global selflessness.
You really don’t though, the work is what deepens the relationship you have with people.
And if you hate your children, you're doing them a vast disservice.
There is no moral imperative to have children, and I wish people would stop pressuring the voluntarily childless into having children.
If I always rode my bike, but didn't have a car, I couldn't really say "riding a bike is as much fun as driving a car".