Oh, I thought that this might have come into play:

Others' comments

It is not necessary to bring talk pages to publishing standards, so there is no need to correct typing errors, grammar, etc. It tends to irritate the users whose comments you are correcting.  

Never edit someone's words to change their meaning. Editing others' comments is not allowed. There are exceptions, however. Some are:
 If you have their permission
 Removing prohibited material such as libel and personal details
 Removing personal attacks and incivility. This is controversial, and many editors do not feel it is acceptable; please read WP:ATTACK#Removal of text and WP:CIVIL#Removing uncivil comments before removing anything.
 Unsigned comments: You are allowed to append  or one of its variants to the end of someone's comment if they have failed to sign it. The form is {{subst:unsigned|USER NAME OR IP}}, which results in —The preceding unsigned comment was added by  (talk • contribs) ..
 Interruptions: In some cases, it is OK to interrupt a long contribution, either by a short comment (as a reply to a minor point) or by a headline (if the contribution introduces a new topic). In that case, add "Headline added to (reason) by ~~~~"). In such cases, please add {{subst:interrupted|USER NAME OR IP}} before the interruption.
 When a long comment has formatting errors, rendering it difficult to read. In this case, restrict the edits to formatting changes only and preserve the content as much as possible.
 On your own user talk page, you may remove comments from others, although archiving is generally preferred. The text of another user's comment, however, may never be directly edited to misrepresent the person or change the meaning of the comment.
Must be tricky deciding 'when' to be 'diplomatic' or to cite rules when they are broken. I will pay more attention to see when it is appropriate.  | Talk