This is a tough one and agree with MadPick (shocker I know)...
To make it really work... it takes people to do their part. But when you have a lot of 1 posting - just to sell or buy... they don't learn the "ropes" enough to really make it smooth for everyone.
To keep it absolutely clean - takes work. Takes people to actually go into almost every post to check and re-check and re-check on a "regular" basis. I loved deleting for sale items back in the day... but I had lots of down time at work and so I had lots of time to browse almost 2-5 times an hour...
The admins, mods and volunteers of this site do their best but it's a free site. There isn't someone on 24/7 (but it sometimes it is...) but when the admins, mods are on... they are typically focused on keeping some folks from getting out of hand.
For those that want to help... and really want to bug a mod... PM them with a link