ACA-we get a lot of spam on AAM. The moderators aim to remove it as quickly as possible. There is no guarantee that there will always be a moderator monitoring the site. If spam remains for, say, more than 5 minutes, use the 'Report Bad Post Function' to ensure that all moderators are informed.
Volumes appear to be higher, or at least more noticeable, some weeks over others.
All the threads you have linked to above have already been deleted.