And you know this how? Are you sure Mars is sterile? Of course not.
It is a foolish endeavor to bring material from a planet that may harbor life in some form. You may trust the Russians or Chinese to 'do it right'. I certainly don't.
These are the same people who poison their baby formula (and ours), their land, sea and air. The Russians who just a few decades ago released anthrax in a bad accident. THE CHINESE, who use fetal parts in makeup. I agree that neither country is trustworthy when it comes to protecting human life in any manner. They both are still very centralized powers, which is a large part of the danger, IMO.