People should obviously not be judging you for not having kids, but I think you misunderstand why most people do have kids. When they say “I just wanted to” it’s not because they don’t have a reason or didn’t think about it. It’s because the reason is so deep and visceral that it’s very hard to articulate. It’s like asking someone why they want sex. How do you possibly answer that? Nobody should be asking you why you don’t want sex, but neither should they be asking you why you do. The need just is what it is for different people.