I've just seen your flag, and deleted both comments. Do not criticize, even if someone else has been less than tactful. Do note that the advice is appropriate, even if not entirely polite—please don't overformat.
A more general answer follows.
English Language and Usage is intended to be a location where linguists, etymologists, and serious English enthusiasts can gather to learn more about the subject professionally. In this vein, we do not allow personal attacks or other non-constructive criticism.
If this has occurred, you have several options:
You can flag the offending post or comment. This is generally the preferred technique unless the problem is excessive (i.e. it goes beyond a few posts and continually defines the individual in how they participate in the site)
- If it is entirely offensive, select "it is not welcome in our community" for posts or "rude or offensive for comments".
- If only parts of the post are offensive, you should select "it needs ♦ moderator attention", then "other", and explain.
- If this is a continuing situation and not a one time offense, you can flag any offending post and explain the situation and we'll take appropriate action.
- Of course, you can always select another flag option if that one is more appropriate.
You can email any of the site moderators if an email address is available on their profile (for example, my profile has my email in the profile text box)
You can post here at Meta.English if you are comfortable talking about the incident in public
The exact nature of how we deal with the situation will of course depend on the severity of the offense—it may be as simple as an edit and it may go so far as post deletion and user suspension.