No, is the short answer.
It should not be flagged. It should be downvoted and a comment left explaining why it is incorrect.
This clearly leads to the question:
Why don't we delete bad answers?
There is a reason why the standard flag rejection message exists:
declined - flags should not be used to indicate technical inaccuracies, or an altogether ...
Use the flag "In need of moderation attention" and then specify why it should be migrated and where to. It doesn't always work, depending on the length of time that the question has been posted for and some other factors, but often it does work.
The answer to "Why?" is simply because it hasn't been set up by the moderators. Generally, a specific migration "...
Some new moderators were appointed yesterday, see Pro Tem Moderator Announcement. Hopefully the new moderators can keep up the sterling work that the previous moderators have provided up to now... :-)
After a minor marathon session of clearing the backlog, all flags have now been cleared. Hopefully in a way that keeps everyone happy:
Some (one or two) ...