I don't think DMOZ had ranking per se? They could mark "preferred" sites for any given category, but only a handful of them at most, and with very high standards, i.e. it needed to be the official site or "THE" definitive resource about X.
You are correct, the sites weren't "ranked" the same way that Google ranks sites now. But there were preferred sites, and each site had a description written by an editor who could be fairly unpleasant if they wanted to.
I had a site that appeared in DMOZ, and the description was written in such a way that nobody would want to visit it. But it was one of only a few sites on the internet at the time with its information, so it was included.