Zizek is anti-capitalist. He is arguing against the enclosure of “charity” within a capitalist system. He is not arguing that non-profit should be replaced by for-profit. He is arguing that this type of “charity” only prolongs the evils of the existing system. He says “The worst slave owners were those that were kind to their slaves” — this statement is not an endorsement of slavery and it is a deliberate metaphor.