That's not to say there aren't rules, but rules are decided by collective decisions (or in practise the collective decisions of people from 15 years ago) and are implemented based on argument, debate and evidence. Usually when people say an "authoritarian" governance model, they mean there is a ruler or small class of elites, and whatever they say goes, no discussion, no debate, no appeal. That is very much not what wikipedia is like. It is however what a lot of social media sites are like (good luck appealing a fb moderator decision)