When people talk about 'gibs', they aren't talking about the government assistance provided to people like them. They're talking about the (functionally identical) government assistance provided to black people.
See: 'illegal immigrant'. The phrase could, and in a literal reading does, mean anyone entering the US illegally. When politicians talking about deporting 'illegal immigrants', it's understood that they mean illegal Mexican immigrants.
In the same way, 'gibs' could, in theory, mean any government handout. However, if you examine its specific usage you'll see a clear pattern.