I have flagged for moderator attention a user's answer (to a meta question) in which this user baselessly questions my nationality and integrity. This flag pending, I realised that the user's answer is further in error for a different reason, because it does not address the original question. I wanted to flag it again for this reason, but the software does not support it. Is it true that I can have only 1 pending flag on one post at a time?
It's possible to raise only one flag at a time on a post, and generally only one will be entirely apposite. Even where there does exist a possibility of more than one flag, one will be more appropriate than another. Some flags are handled by the community; others go straight into the moderators' queue and don't get presented to the community.
Although it is possible to retract a flag if you want to change it to another, you cannot then flag the post with the same type of flag for a second time. Thus, if you flag a post as spam but then change your mind and flag for Not An Answer, you can't change your mind back and decide it's spam.
For these reasons, you need to consider all possible flags and it's advisable to raise the most important flag first. If a post really needs a moderator to look at it, then by all means explain what's wrong with it. But if it's simply a low-quality answer, or doesn't actually answer the question, then it can be dealt with by the community. And spam should definitely be flagged as spam because the system itself is involved.
In the case of the answer you flagged, you used a custom flag for moderator attention and explained exactly what was wrong. Not only was the post not an answer, it contained unfounded and inaccurate opinion about a particular person. That was arguably more important than flagging it with the bald "Not an answer" reason. You could possibly have flagged the post as abusive, but the more detailed explanation was better, in my opinion.
And, as if by magic, the post was removed.
Note that if a post doesn't really need moderator attention, the result of a moderator-action-please flag is not necessarily predictable. Although a moderator may agree that immediate action is necessary, the flag might be declined instead because the post could and should have been dealt with by the community. There are a number of standard reasons for declining a flag:
- flags should not be used to indicate technical inaccuracies, or an altogether wrong answer [comment or vote rather than flag]
- flags should only be used to make moderators aware of content that requires their intervention [Not an Answer or another "community" flag was more appropriate]
- a moderator reviewed your flag, but found no evidence to support it
- Using standard flags helps us prioritize problems and resolve them faster. Please familiarize yourself with the list of standard flags: see What is Flagging?
The help pages on flagging are well worth a read.