Okay, I've never heard anyone who puts any emphasis on social justice as a Christian who should be following Jesus' teachings from the gospels claim any of these things, that all rich folk are evil oppressors, hint that you must give all or even most of your money to the poor in order to be a "true Christian (tm*)", or that any form of sin or wickedness is ultimately okay as long as it isn't greed. Whoever's been saying this or teaching it to you sounds a lot like they just want to demonize social justice so that they can have an excuse as a Christian not to bother with carrying out any of the pretty plain commands from the New Testament to care for the poor and give justice to widows and the oppressed.
(And to be sure it is not misunderstood, if I speak of social justice as a good thing that had a pretty strong basis in Jesus' teachings, I do not mean that social justice which involves shouting down with a megaphone anyone who walks by just for being a straight white man with a bit of money in his wallet. Not everything has to be an extreme.)