Well, that sentiment entirely misses the point of all of this!
So the poster above is noting that if people were, or we would have, been okay with having kids in the past, then we still should today.
"Is it still OK _for the planet_ to have kids...", not "Is it still OK _for the kids_ to have kids..."
EDIT: actually, I'm not sure which one of those the representative was getting at.
That's a strange question. The planet doesn't have feelings, so it doesn't really care whether or not we have kids.
Other living organisms on the planet may care. But the rock we're on surely doesn't.
This is exactly why it misses the point. Having kids is a significant contributor to carbon emissions, and therefore climate change.