I don't mean to get involved, but I see exactly why the administrators are not banning Seether. Being a small time admin in my past. I know that it's almost impossible to keep someone from changing their account, or even worse keep someone from changing their IP address on the internet, or even device for that manner. Seether I think he or she knows this already, the best advice I can give is either to ignore his or her posts or in my case, just reply if he or she actually contributes to the forum in a positive way.
People like him or her just don't give up, until their all burned out mentally or get more mature.