This have been happening since, at the very least, yesterday afternoon. A lot have already been deleted, but I guess the mods can't possibly hover around 24/7 to do it so some stays around for a while.

Maybe they are giving up manually deleting them and are working on trying to figure out on how to automatically delete those and/or preventing them, cause in all likelihood those are bot generated and it's just not feasible to keep up with using manual deletion.

Different moderators are in charge of different sections.

Unfortunately, we're not around the clock 24/7. We do sleep after all : D
The spam threads will be deleted (Or already has been)

Thank you for informing us.