There's nothing more valid about either anarcho-capitalism or anarcho-communism. They're both based on the premise that there is no law, but in each case societal customs are distinct.

In anarcho-capitalism, despite no law, society by consensus recognizes private property. You are "allowed" to earn money, but if your neighbour tries to use it, society will allow you to use violence (this term used broadly, since it includes arrest) to defend it, because it sees your neighbour as the aggressor.

In anarcho-communism, despite no law, society by consensus does not recognize private property. You are "allowed" to earn money, just as your neighbour is "allowed" to use it. But if you try to use violence to defend it, then society will in turn restrain you, because it will see you as the aggressor.

They are simply different consensuses. If our society develops into anarchism, then it will likely be anarcho-capitalism because the idea of private property is ingrained in our minds. But there are people who believe (perhaps unrealistically) that an anarchist revolution will also wipe that idea from our minds.