A pejorative used by hawkish, austerity-loving conservatives who think they're Liberals because they're not or barely not racist or anti-gay. Emoprogs make fake Democrat get their undies in a bunch because emoprogs insist that Democrats act like Democrats and not like Reagan Republicans.
Billy doesn't want to bomb Damascus with depleted uranium shells, he must be an emoprog.
Susie is an emoprog because she won't meet the republicans half-way on cutting Social Security earned benefits. But screw the elderly, I want a tax cut.