Spam vs abusive pms.

There is a banned poster who is using multiple accounts to vote posts down and send abusive pms.

When I start a thread about it the mods remove it.

Now Ican understand that it could be against tos, but what I do not understand is the way pms are dealt with.

If I report spam the pm is removed, the sender's name is still visible but the first visible line of the message says [removed]

If I report a personally abusive pm it stays.

I would rather go to my inbox and see something like rate my pics or hot escorts in Islamabad than this,

" How's the penis licking going? The best thing is that you're going to die knowing.."

This crap has been going on for years now, the mods say thank you when you report it, but they don't seem to be doing much about it if they won't remove the offensive message.