Many of these "new" accounts are not new at all but repeated attempts to get coin from those that are too trusting and Neutrals are mostly ignored. I see nothing wrong with a Negative. OP can work with suchmoon on this issue.
I don't even know why newbies care about their trust ratings that much.If they're fair in approach,they'd still get the exchanges done anyway.As long as suchmoon's policies are concerned, or from (what I have noticed) the feedback would stay up for a few weeks,if OP completes a good number of trades in the forum without any issues then maybe after 2-3 months he can approach such to have it removed.Of course with the valid vouches.
@OP : Mods won't lock the thread,do it yourself by pressing "Lock Topic" on bottom-left side of your thread.