This is off the mark. The launch of the War on Poverty featured a very fragmented, decentralized system of programs aimed at self-help and mobilization of the poor. Nixon's effect was to turn everything into income support (cash and in-kind) which implied a more passive recipient population, not a more fragmented one. The distinction between deserving and undeserving, giving rise to social insurance for the former and means-tested programs for the latter, predates Nixon.
The group phenomenon is associated more properly with the rights-based movements (civil, women, gay, disabled, etc.), towards which Nixon was not particularly solicitous. I'd say the left is more at the root of such fragmentation than Nixon.
mbs