The thing is that in case of small merit abuse transacations as 1 merit ,Negative trust is good enough, it would not allow them to particpate in sign campaigns which would stop their spam.
Receiving Merit on a low quality post is not a valid reason to for red trust. That could easily be abused to target a certain user.Congrats on being the first non-founding member to reach 1,000 merited points! 
Thanks 