The only thing that really is trust abuse is lying, with a few exceptions.
That is a ridiculous assertion. Both positive and negative ratings have a clear description and if the situation doesnt match the description (reasonably), it is abuse.
Being a troll has nothing to do with the chances of someone not honoring their obligations in a trade, which is what the trust system is supposed to help people measure.
The same can be said in many other reasons for giving out ratings.
Thats not true. Behavior does have an influence on whether you'd trade with someone or not. I personally would not trade with someone who exhibits concerning behavior. The trust system is supposed to be about accurate feedback for members, the content is more or less decided by whats acceptable by the community, and to this point, giving someone a negative for trolling, being an account farmer, owning multiple accounts, being racist, etc isn't something thats unheard of. It would be abuse to claim that the guy is a serial scammer because of their behavior. It isn't abuse to point out that behavior however.
I personally wouldn't give out negatives for trolling, but I also wouldn't give out negatives for owning multiple accounts or account farming, and thats the generally accepted practice by the community. I however certainly would give out a negative if it was for harassment or something of that nature.
Again, I didn't read through Cryptohunter's posts to prove to myself whether there is anything worth being concerned about from their posts. My position is that if the behavior issue is subjectively accurate, then its worth noting. I'm not claiming the claim itself is accurate or not, I'm claiming that the basis of the claim, if accurate isn't abuse.