If you have a negative utilitarian moral outlook, it follows that if some beings will suffer by existing and its not possible to know which beings they are in advance, then bringing any beings into existence willfully is morally wrong. I am not a negative utilitarian myself, but the position is not selfish, crazy, or based on personal unhappiness: people who themselves are very happy can be negative utilitarians. If those happy negative utilitarians see unhappy people in the world, they can then come to the conclusion that they should be antinatalists, even if they are themselves happy.

By the way, asking people "why don't you kill yourself" is not very nice. Even if you disagree with someone's moral philosophy, jumping to "why don't you kill yourself" isn't going to win anybody over or garner you any understanding.

https://en.wikipedia.org/wiki/Negative_utilitarianism

If I'm getting this right, that they think that they'd rather not be born, I think it's a perfectly reasonable question. To not be born and to remove yourself are close enough.

They aren't close enough and this demonstrates that you don't understand the position.

It also suggests that you didn't read the article.

> Why don't you kill yourself.

It's important to note that the anti-natalist position isn't the same thing as pro suicide.

It isn't even a suggested solution to the problem.

This also isn't a depression issue. You can be happy (define this however you want) and hold the position that it is preferable to not exist.

Once life starts however, it is probably a better option to let it run it's course. The anti-natalist position is just that never existing doesn't have any downsides.

For example, how were your first 13.7 billion years?

For what you consider the most obvious question what do you think some of the most obvious responses might be?