I think that the editor seriously overreached in this instance, and that the editor's emphasis on erroneousness and misspeaking—as opposed to real-world usage taken at face value—altered the nature of the question asked and the sense, tone, and relevance of the answers that were submitted in response to the question as originally formulated.
The proper approach, in my view, would have been to add comments contesting the validity of the question and of any answers that the editor found flawed, and to submit an answer that made the editor's case at greater length than might be possible in one or more comments. The editor in fact did both of these things, and was well within his rights in so doing. But changing the original question and two or three answers to comport with his views was, I think, a mistake and should not be encouraged.
The legitimate weapons at every high-reputation user's disposal in promoting a particular view of a question are commenting, upvoting, downvoting, and answering. I consider editing an inappropriate tool for such promotion. The central purpose of editing is to help the poster say more coherently what the poster intended to say but somehow failed to say well—and perhaps (in extreme instances) to make a promising question or answer that is in danger of being closed or deleted acceptable under the site's guidelines for asking and answering questions.
Editing questions and answers to make them reflect one's own ideas of correctness—or (in the worst case) to vindicate a peeve—doesn't fulfill the purpose for which we are empowered to edit questions and answers. I am confident that if the changes that occurred in the present case had been submitted through the Suggested Edits queue, they would have been rejected as being inconsistent with the original posters' intent.
I hope that this answer isn't taken as a personal slam of the editor who made the changes. He has made numerous positive contributions to EL&U, I have never had a hostile exchange with him, and I find his enthusiasm and lack of pretense refreshing. But I do think that in this case he exceeded the bounds of appropriate editing, and I would roll back all of the changes he introduced to the question and answers here.
