The widespread existence of secondary markets for SNAP benefits, which convert subsidized food for poor people into cash, carries this implication. This is pretty normal in some poor communities and that cash is commonly diverted to various vices. Some malnutrition is a consequence of this. Adding friction to the conversion of welfare benefits to cash is a feature.

You can't force poor people to spend cash on proper nutrition and a minority of them don't. It isn't a moral judgement but an observable fact. A lot of policies around welfare are targeted at trying to prevent this minority from slowly killing themselves in public.