I think your description of them says a lot about your arguments nature.
I mean of course the parent are to blame, but since they too belong to what you describe as underclass they simply do not have the mental surplus.
If you have kids you will know how hard it can be to control their whereabouts.
And as far as I can se, no one is claiming it's an excuse. It's an explanation. You can then as you do choose to disregard it or you could perhaps try and look at the root cause and accept that social status and income do have an effect.
I mean of course the parent are to blame, but since they too belong to what you describe as underclass they simply do not have the mental surplus.
If you have kids you will know how hard it can be to control their whereabouts.
And as far as I can se, no one is claiming it's an excuse. It's an explanation. You can then as you do choose to disregard it or you could perhaps try and look at the root cause and accept that social status and income do have an effect.