Well, your negative trust has nothing to do with his account considering he is a newbie. But both Negative and Positive Trust is not meant for that. Just quoting the post and shitposting doesn't mean that you don't trust him. So, if you see a quality poster will you trust him?
As the trust quote says,
Warning: Trade with extreme caution!
What did he actually do? Did he scam anyone or has he traded with you and you don't trust him?
We should give time for newbies to use this forum and understand how it works. Even though he may be a legendary guy, you should not distrust him. Trust is not meant for that.
Regarding spams, I report and mod removes those posts. If the user repeats that, I always PM them stating that they are spamming. Some have realized those and started posting meaningful.