Of course taking care of the mentally/cognitively impaired is different from the criminal, although the percentage of criminals with cognitive impairments and serious mental illness would probably shock you. Each of the many groups (not an exclusive list) are different from each other in what they need and deserve--those are each very separate discussions. 


But you actually did advocate that those who cannot take care of themselves be thrown to the wolves because you left them out--they are most often not in your basic premise: "Each of the 320 million inhabitants in this country know what is best for him or herself" (a pretty sweeping and ideological generalization). Also, you apparently would be surprised how many of the poor you are separating out as the "non-deserving" of entitlements are exactly those who are cognitively impaired, seriously mentally ill, children without parents, etc. That may be as far as we can agree, because that is where your ideology sweeps people away.