When we allowed 20% of the population to assume ownership of 80% of the wealth, forcing everyone else to scramble for scraps. When we've dismantled and made useless our social safety nets by a combination of poor policies and equally poor policing for abuse. When we've collectively moved to the right in economic and social policies, thereby not only disenfranchising the poor, but also make them hate themselves - the loudest complaints about "socialists" and "redistribution" seem to come from people who need it the most, but don't recognize it.
It happened when we started penalizing people for having anything less than perfect health. Have a chronic condition? Well, forget about entrepreneurialism and adding to the economy, pray for a worker-cog job for the rest of your days to keep the insurance flowing!
This may be a gross simplification of a complex issue - but it seems to me like the futured turned into a game of Survivor when we started treating everyone else like animals out to get us. The poor are lazy and out to game the system. The immigrants are out to steal our jobs. The unemployed are lazy and slovenly and want a free ride... etc etc.
The American public, IMO, needn't look much further than a mirror to see the cause of their woes.