Deleting helps in cleaning but doesn't undo an offense. This specific case was unclear so I left it at deleting (explained in my comments I'll delete as not needed any more and in chat).
Some other background that can help moving on.
To answer that quote "Because obviously flagging is not the way-to-go.":
It is the primary way to go. Just flag in a very clear way.
Quickly some examples including clearly abusive stuff and stuff, that may or may not be considered as offensive but should be removed in any case (plus giving your opinion too):
<this post> is abusive because of
<this post> is off-topic, and it even looks abusive to me because of
<this post> is no longer needed, and it even looks abusive to me because of
1. may sometimes be hard to confirm because there because there can also be irony, sarcasm, satire, misunderstanding, and I do not easily put a stigma on a user ("has been abusive"). Especially since flagging as abusive can also be used against others because of another ongoing conflict.
I'm more than happy to delete a post that's cleary abusive. And even if unclear, I'm also happy to delete a post that is off-topic or no longer needed, as those are usually valid reasons to get rid of such undesired comments.
To sum up, bad comments can easily removed by flagging, because there's a lot of reasons if it's not purely texnical. We do it a lot, though like 90% are just flagged as no-longer-needed (such as very old welcoming comments).
No complaint but answering: in this case here,
- the flag was not placed on the specific post (since that post had been deleted) (now I don't even find this processed flag anymore in histories with 20 min searching)
- an answer has been linked as being abusive, but it wasn't (I think you meant one of the comments)
- that comment was not friendly but doesn't look dramatic to me to justify flags (abusive or harassment) and meta post follow-ups and mod acting on the user (warning? suspension?) who already removed that post (we can talk about this)
- that comment has already been deleted by the poster before the flag
- the whole answer has already been deleted by the poster before the flag
- what should a mod do now since deletion was already done and it doesn't look like anough reason to follow-up with warning or suspension
For completeness, some generic examples of rather unclear flags, hard to handle:
<this user> is harassing me (what now, shall we try to find something? give links or post flags at where it happened)
<this user's> actions in
<for example review queues> are not good (shall we read all stuff for quality assessment?)
The more specific and the more justified the clear reason, the better.
Mods are happy to act on a clear flag. Unclear flags though may sit for weeks in the flag review queue since it's neither clear to confirm and not clear if it could be omitted. In any case it's noted. And if there is a serious issue, it may show up again on another flag. If on the other hand it never happens again, well, peace perhaps.
To close the circle, flagging is better than attacking back or going into discussions that are actually not about convincing but, frankly sometimes about winning and being right and nobody steps back and it can escalate.
Let's flag and remove stuff that doesn't belong to the TeX content on the main site.