As they are using same contact info they all are alter. And also they are trying to trade all reversible payment which seems to me scam. What do you think?
Some DT members may place a negative trust for trying to sell PayPal accounts or using irreversible selling method. "Just as happens with loans."
Generally, Bitcointalk official rules do not prevent you from having more than one account as he has not proved to be scammer "using an alt account to hide negative trust."
Maybe report to mod if you feel that he is spreading spam after verifying alt accounts.