I saw this answer (and asked another, unrelated meta question about it). Looking at the edit history, the edit substantively changes the meaning of the answer. I.e., the original answer says that WD-40 works ok for the problem in question and the edited answer says to never use it. Whether or not you agree with WD-40's use as a bicycle lubricant, is it ok to edit an answer in away that substantially changes the meaning of the answer?
This is an area where users and moderators should tread lightly, but I do think there are situations where it is ok.
In the example you posted, the entire answer and it's meaning wasn't changed. The original provided 3 possible solutions (Light Oil, WD-40, and Synthetic Lubricants). In this case, an edit was proposed to change "WD40 works OK" to "Never use WD40."
Because the user who suggested the edit did not have sufficient reputation, it was flagged for moderator approval, and was later approved (which is why it's attributed to the "Community"). If the entire answer had essentially been "use WD-40" it's likely the answer would be downvoted to oblivion, or flagged for deletion. As it is, the two appropriate parts of the answer were left. There have been similar cases where erroneous or dangerous advice has been edited out of a question, and removing any reference to WD-40 may have been a better choice.