There are few solutions but sadly admins never considered them:
- Prohibit new members from posting. I think 1 week would do fine.
- Wait for approval of posts from new members.
- Add new roles for trusted members, who would for example delete offensive, non-steam related and spam posts.
As far as I am concern, this forum does have an anti-spam functionality which checks if a member's IP address is black-listed in SFS (stopforumspam). The best thing to do would be reporting spammers to VPN (hosting-related) providers and judicial systems around the world. Unfortunately, China is the only country that has a court dedicated to the internet.
https://en.wikipedia.org/wiki/Hangzhou_Internet_Court