You don't need siblings to have a happy life, nor do you need private education. Both are optional extras for people who have a child.
I don't care what peoples reasons are for not having kids. Just don't have any you don't want, that is repugnant behavior.
I would have a houseful if we had the cash to provide for them all. Money buys options, it means that if for some reason state education doesn't work out you can pay for something different, it buys gear and instruments and experiences, all things I want for my children.
I do believe that it is better for my third child not to exist than to have to split the resources we have available, obviously I think that.
It isn't creepy to want to do the best for your kids, just because you don't believe a private education is 'best' seeker doesn't mean everyone has to agree with you.
I do what I believe is best for my kids. And for us that means limiting their siblings. A cold hard decision that puts what I believe they need above what I want.