Disclaimer: This is all my opinion, please consult an attorney for legal advice
Actually in terms of legal problems one of the primary issues is the faith in which the name was registered or purchased. In many instances bad faith will be indicated through blackmail-like practices in which the registrant seeks to hold the trademarked name (or dn derived from such) hostage against the rightful owner. The sum of this is that to try and sell for a profit may indicate that the name was registered in bad faith. However the likelihood of a TM holder coming after you is likely minimal given the low visibility of the domain.
It is acceptable to develop a domain as a "protest site". That is the way our market steers towards efficiency, by allowing consumers to voice grievances by naming the companies that do them harm.
In conclusion, most names like this have little value in general because:
1. Potential for legal action
2. Buyers are not willing to pay a significant premium based on the limited use (non-profit/free speech site)
get rid of it for reg fee and the benefit is no liability/chance to get another site in good faith
Hope that helped out...just my opinion