...yet I'm seeing unironic comparisons to both 1984 and Nazi Germany, so ... what this person did is evil?
Can someone please help me understand this?
Even though this person is a lone wolf, their actions feel disturbingly authoritarian. This level of compulsion and control is immensely off-putting to the average person. Anyone who puts this much effort into controlling information seems like someone worth confronting.
It's not so different from if a Brit tried to change every instance of "color" to "colour", or an American changed every instance of "colour" to "color". It would be incredibly annoying, patronizing, and disrespectful.
Wikipedia is not a place for people to wage their private grammatical language wars, and so people are responding in a negative way because the editor is trying to impose their viewpoint by sheer force rather than respecting contributors who choose to use Merriam-Webster's 2nd definition of the word.