That means it can be forked if it turns out they are doing more than protecting people from harassment. For now let's give them the benefit of the doubt.
It also has public change logs, so it is easy to have a debate about the presence/absence of censorship.
Wikipedia's protective moat isn't the licensing, it's the SEO. You can't compete with that under any circumstances. There is absolutely nothing you can do about it. Fork all you want, your content will never show up in Google's results with a high ranking, and as such you won't get a large enough audience or editor base to matter.