Is slavery cannon to the modern RWBY world?

This really boils down to if the comic series is cannon or not because in the Weiss comic she frees three 'political prisoners' who would be used as slaves and we see Blake and Adam freeing several Faunus from a cage in a dust mine. I've heard that it's both cannon and non cannon or just cannon or just not cannon. So what's going on because I feel like the addition of legitimate slavery to the world of remnant does fundamentally change the world and narrative in a few ways?