What's interesting to me is that I've known people with both
  philosophies my whole life - formulated EXACTLY like them, yet
  never heard of a name for them before.

  I mean, there isn't a adolescent on the planet that hasn't said
  at some point, "I didn't ask to be born" to their parents or...
  at least to themselves.

  Because... none of us asked to be born, yet we're here.

  Antinatalism is a logical extension of that. If it's not fair
  that I was born, then it's not fair that anybody is born.

  I'd say a majority of friends I've had through the years are
  non-procreators by choice. They have some very elaborate
  philosophies why procreation is bad on a moral level and a few
  it's on a personal morality level.

  So my surprise was that I hadn't seen words for it before.
  Often, antinatalism [now that I know the word for it] is a
  logical justification for abortion for example. In various
  discussions through the years, the hypothetical, "Why should a
  child be forced to be born to parents that don't want them?"
  comes up.

  That would be an antinatalist argument. So, I don't think it's
  unpopular per se, but rather that there's a word for it that's
  an evolved philosophy all on its own by itself, unrelated to
  other social issues is what surprised me a bit.