I've noticed the same trend. It tends to come and go, but I agree it would be great to have a few people able to remove spam. Weekends with a big sporting event seem to be the worst.
I think the main complication is that once a post is removed, the account is still active, so it would not take much for the spammer to simply repost as needed to keep the message up.
It would be interesting to see a "review" system for "new accounts". Imagine accounts with fewer than 250 points have their posts (Tutorials, Questions, Discussions, Models...etc.) sent to a queue. Once a few legitimate users press the "OK" button, the post is made.
The biggest complication is the lack of instant results. Maybe it takes some minutes to see a post make it to the site? But the advantages are better posts. And, a reason for people to try and reach that 250 point threshold by being more active members.
I was stunned one weekend to see a Question post get ~6,000 views. The post had something to do with a streaming video or TV site. I always found this site slow on weekends. A "real Question" post might get half a dozen views. But someone must be here to push a spam post into thousands of views.