For many people, it's difficult to conceptualize having meaning outside of having a family. After all, it's one of the most selfless and involved choices a person can make, and it admittedly gives a lot of people their raison d'etre. That being said, there are so many people who lead interesting and meaningful lives without having children. While being a childless, dual-income adult seems to have sprung up in popularity over the past couple of decades, it's by no means a new phenomenon.
Some people see a stark difference between not having kids because your life is full enough as is and not having kids because you are lazy and don't want to "waste money" on anyone other than yourself and your partner. Some of the reasons childless people say online as their reason for not reproducing might seem flimsy at best, and they enrage no group of people more than trad parents.