A friend of mine recently commented, wisely I think, that "social justice" is neither social nor just. In broad, general terms, I tend to think the same of the so-called "social gospel." Since "social justice" must mean societal justice, it is notable the "social justice movement" seeks not actual justice, but power. See, for example, the way in which it divides us into classes and seeks to delineate their disparate treatment, which is the opposite of what Christianity teaches. In the same way, the so-called "social gospel" in my observation, and again speaking perhaps over-broadly since people can self-define as they wish, seeks not the application of the Gospel of Christ to society, but rather worldly improvements. Worldly improvements are certainly worthy goals apart from the Gospel, but the problem with "social gospel" activists is they so rarely use the Gospel to bring about those improvements. If you want evidence of this, you need only visit the websites of the mainline churches and look at their solutions. While they certainly are couched in language of Christian morality, they too-often seek political solutions.
That is, too often, they seek imposition of power, which is emphasized more strongly than change of the human heart. Not to the exclusion of the latter, but certainly in greater emphasis.
I do think the same could be said of evangelical conservatism, for what it's worth. One thing I really appreciate about the Orthodox Church is the lack of naked partisanship from the Church leadership. You have it -- often detrimentally -- from individual Orthodox Christians, sometimes priests, and rarely bishops. But for the most part the Church stays out of power politics and simply addresses societal issues. Perhaps that is due to her long history of living under oppression, but I would argue that is a feature, not a bug. We have learned to be the Church even in a world that opposes us, and so we do not feel the need to seek political power to impose the Gospel on a dying world.