There's still a small core of long-term editors at wiki who take their encyclopaedic role seriously, and try to avoid bias. There's a much larger group who are openly activists but justify their narrative-moulding with lines like "reality has a liberal bias".
Anyone can create an account to become an editor, but if you go against the dominant clique you'll be bullied out pretty quickly.
Most editor accounts are zombie accounts, and the number of active editors is much smaller than people think. It's mostly people who are highly motivated and have lots of time on their hands, and overwhelmingly male. Certain niche subjects can be squatted by a handful of editors. Or foreign language editions - the Croatian wiki was run by a group of neo-fascists for about ten years before the Americans caught on.
The main way bias is introduced into the process is through the list of reliable sources and deprecated sources. Reliable sources in English would be the BBC, CNN, NYT, WaPo, Guardian. But also more contentious outlets like Pink News and Vice Media. Meanwhile, you can't use Fox News for anything political or cultural - though you might quote a local Fox affiliate on a straight news story - and you can't use the Daily Mail as a source for anything.
What this means is, let's say for talk's sake that a major scandal in the UK is being covered by the Mail and GB News, but the BBC and Guardian are refusing to mention it. In that case, as far as wiki is concerned, the scandal doesn't exist.
That's why I might use wiki for "what is the capital of Madagascar" type questions, but not for anything politically or culturally controversial. I've seen too many blatantly agenda driven pages, and when you look at the talk pages you get to see how the sausage is made.