Anarchism covers lots of different things— If there’s one leading principle which unifies them, it’s a simple one. It’s based on the assumption that any structure of authority and domination has to justify itself – none of them are self-justifying. Whether they’re in individual relations, or international affairs, or the workplace, or whatever- they have a burden of proof to bear, and if they can’t bear that burden (which they usually can’t), they’re illegitimate and should be dismantled and replaced by alternative structures which are free and participatory and are not based on authoritarian systems.
Sometimes they can be justified, so it’s not that it’s always impossible. Like if I’m walking down the street with my 3-year old granddaughter and she races into traffic, and I grab her arm and pull her back that’s an authoritarian relationship. But if challenged, I don’t think it would be hard to give a justification for that relation of authority.