It's bad since they allow it but they they give you red trust. Dont understand that.
The reason for the red trust is a precautionary one. Scammers often use bought accounts to defraud people by pretending to be upstanding and established members of the forum. They insist that coins, money or goods be sent first to them, often without escrow protection.
Tagging the bought account with an advisory or negative feedback helps by giving advance warning to anyone trading or transacting with that account. I support this practice. It allows those who interact with bought accounts to take the usual precautions such as using escrow and never sending money or coins upfront.