It's idiotic that plagiarism gets a permaban but blatant scams are allowed...but that's the way it is. Complaining about it isn't going to help your case.
Copying and pasting is pretty cut and dry whereas scamming isn't always or will require a lot of time and effort from staff to investigate, hence why it's largely left up to the community police. Personally, I wouldn't be against removing blatantly obvious scams or ones that are very likely scams but I can see how that policy would open up a huge can of worms and people complaining why we removed X but not Y etc.