They are overlapping. Moreover, "parents on the margin of incarceration" are an extremely significant group of parents for whom the discussion of "supporting families as is" vs. "ripping apart" is meaningful at all. For most poor families it's irrelevant as there's no grounds for dissolution.
I believe you can't deny that it's much more common and publicly acceptable to claim that such a criminal parent should be shown leniency when possible, because having no parent at all is horrible. Yet we have evidence to the contrary.
I concede that this may be inapplicable for some other cases (or at least that we have no proof that it would be applicable yet). However, I personally think that those "at risk families" where parents create an atmosphere that's detrimental for stydying (by being aggressive, anti-intellectual etc.) may well be worse than outright criminal ones, and I believe it'd be proven in due time.