Gamergate was the first completely deceptive article I noticed on Wikipedia. Now we have so many including the one on Kiwi Farms.
I often hear it said that the turning point was Trump. His election broke people's brains, and we see a shift then on Wikipedia from trying to write neutral articles, to finding one "reliable source" (Vox or Buzzfeed or whatever) expressing an extreme opinion, which becomes a fig leaf for filling the article lead and text with clearly non-neutral commentary. It helps that the mainstream media as a whole moved to increasingly non-objective reporting around the same time (for the same reason), but Wikipedia could have navigated this situation if it wanted to by adopting policies of filtering out clear editorial opinions. As an example, there could be a policy guarding against attributing views to people (e.g., far right or white supremacist), which they explicitly deny holding.
But the reality is that this shift didn't emerge out of nowhere in 2016, and Gamergate was one of the earliest harbingers of what was happening. Pro-GG editors spent a lot of time on Wikipedia trying to fix things and get the story right, not realizing what they were up against, because at that time they thought it would be fruitful. Today few would bother as it's obvious Wikipedia is captured.
You can still find plenty of reliable sources that present at least an ambiguous view of Gamergate, but those will be dismissed in favor of hysterical commentary. Now even the talk page is locked down, and you'll be called a troll and swept away if you bring any of this up.
On the flip side, there still are old-school editors around. Earlier in this thread I went over the history of the Libs of TikTok article:
The early versions were written in a reasonably fair, neutral manner even in 2022. But then woke editors barged in waving reliable sources and added sentence after sentence about "far-right" and "hate speech" and "false claims" and so on. There's a whole section on the Colorado Springs shooting, which has nothing to do with LoTT at all.
For more established articles, the trend is visible over a period of years. Go back to 2015 or so, and even very controversial subjects are frequently documented in a calm, reasonable way. Today the articles will be nothing but unhinged attack pages.