There's a great article on Medium about Giraffedata: One Man’s Quest to Rid Wikipedia of Exactly One Grammatical Mistake.
Giraffedata—a 51-year-old software engineer named Bryan Henderson—is among the most prolific contributors, ranking in the top 1,000 most active editors. While some Wikipedia editors focus on adding content or vetting its accuracy, and others work to streamline the site’s grammar and style, generally few, if any, adopt Giraffedata’s approach to editing: an unrelenting, multi-year project to fix exactly one grammatical error.
What, precisely, is that grammatical issue? Giraffedata explains it on a personal Wikipedia page (I wasn't even aware there were such things): User:Giraffedata/comprised of
Many people do not accept "comprised of" as a valid English phrase for any meaning. The argument goes that "to comprise" means to include, as in "The 9th district comprises all of Centerville and parts of Easton and Weston." And thus, "the 9th district is comprised of ..." is gibberish.
The phrase apparently originated as a confusion of "comprise" and "composed of", which mean about the same thing, as in "the 9th district is composed of ..." There is a traditional saying to help people remember these two sound-alike words: "The whole comprises the parts; the parts compose the whole."
But "comprised of" is in common use and some people defend it as a fully valid additional definition of "to comprise". Even dictionaries acknowledge this usage, though they all tell you it's disputed and typically discourage writers from using it. See for example Wiktionary.
Here is my view of why "comprised of" is poor writing
As the Medium essay notes, Giraffedata's work isn't always welcomed.
He was surprised, however, to find in the first three months that some people disagreed with his edit, sometimes vehemently. “When the first few people said, ‘Why did you do this?’ I said, ‘Well, it’s not grammatical. It’s not English at all.’ And then finally somebody came and said, ‘You jerk, it’s a matter of opinion! It’s completely valid, I looked it up in my dictionary! You have no right to mess with my article!’” Henderson laughs. “That came as quite a surprise.” He stopped checking the ‘minor edit’ box, to acknowledge that some users might find the change controversial.
Indeed, he acknowledges the controversy on his personal Wikipedia page:
A usage note in the Merriam-Webster dictionary notes that a writer "may be subject to criticism" for using "comprised of" and suggests alternative wording for that reason. It notes that in spite of being in use for over a hundred years, it is still attacked as wrong, but says it isn't clear why the attackers have singled out this usage. Opposition has long been declining; in the 1960s, 53 percent of American Heritage Dictionary's expert Usage Panel found the wording unacceptable; in 1996, only 35 percent objected; by 2011, it had fallen a bit more, to 32 percent (quoted here). OED usage note calls it "part of standard English".
Still, doing this brings him joy:
When asked what motivates him, Henderson says he views his pursuit as similar to that of people who choose to spend their Saturdays picking up litter from the side of the road. “I really do think I’m doing a public service, but at the same time, I get something out of it myself. It’s hard to imagine doing it for the rest of my life,” he says with a laugh. “I don’t have any plans to quit, but I guess eventually, I’ll have to find a way. It’s hard to walk away, especially when I’ve actually accomplished something.”
I understand the compulsion, and I expect many have felt it; after all, Duty Calls.