Negative trust should absolutely not be removed when an account is sold. Engaging in this practice would take away the financial incentive not to scam as a scammer could scam, or try to scam and then lose zero value on their account when they go to sell it.
Negative trust shouldn't be allowed to be given for such petty reasons such as a disagreement especially when the person giving it offers no proof that what he believes is true
The trust system is not moderated. If you disagree with any negative rating that you have then you should try to discuss the situation with the person who left you the negative rating. Trying to potentially fake a sale via a loan is not going to help your cause though.