In terms of declaring themselves "autonomous", I'm thinking (and I imagine others in power are thinking as well) that this is simply done as a statement of protest, rather than an actual serious attempt to form a sovereign government. So crushing this without mercy is politically infeasable, especially given that the whole protest is about police and justice reform. I don't think this sets any kind of legal precedent. Better let them make the statement and let it run its course on its own.