We're not talking about the electorate, we're talking about individual people's decisions to have children.

If you are impoverished (and thus unable to meaningfully effect change in the system that impoverished you) it is irresponsible and bad to have children because the outcomes for those children will be bad.

You may decide that this state of affairs is bad, but that doesn't change the fact that it is still bad today to make an individual choice to have children in poverty.