So you're saying those "outraged" parents don't like it either and don't like to see people freeloading and not taking their share of the pain? They're "outraged" because some people are getting off scott-free?
There's no shortage of humans on this planet, and by the time we're retired, automation will have advanced considerably.
We're not some small tribe in danger of going extinct. It's a terrible argument to say someone who doesn't reproduce is a freeloader. We need less people on this planet, not more. We're on pace to have 10 billion by mid century. That's going to be a challenge to support that many people while not ruining the environment in the process.
I guess the proper response to this in context of the conversation on moral imperative to reproduce, would be, "So what? Why should I care? Either I want kids or I don't, and that's the end of it for me. And since society isn't going to make anyone reproduce, go fuck off."