America is a meritocratic nation that admires personal achievement, but first of all it is a populist nation that insists that public policy reflect popular values. What ultimately divides the two sides, I think, are unspoken images of who the poor are as people. One issue here is moral responsibility. Conservatives hold poor adults accountable for their condition, whereas liberals present them as products of social forces, people of whom nothing can be expected. A deeper issue is competence.
Most liberals reluctantly answer no.
Conservatives see them more externally. They focus on behavior and potential rather than inner insecurities. So they hold the poor responsible, but they also honor them with more respect for their capability. Such images are remarkably impervious to empirical disproof. The evidence for these is weak, and even if it were stronger, it is difficult to imagine circumstances where the academic left would put any onus for poverty on the poor themselves.