Earlier quoted context omitted.
mens rea
You don't have to intend to commit a crime to have mens rea. You merely have to intentionally do all the steps involved in the crime. Ignorance of the law is not an excuse, and neither is intentional ignorance of whether you are breaking it or not. Pawn shops got the receiving end of this deal a while ago. Now it's Amazon's turn.
Only in cases of strict liability are intentions not usually considered, which mostly include minor offenses (infractions) and a few major ones like statutory rape. Possession of items that are illegal to possess in any situation is another case where strict liability applies, but possession of legal goods that “a reasonable person” would not be aware was stolen does not fall into this case. Amazon sellers sign a contract saying the goods they offer for sell are their legal possessions to sell, giving Amazon plausible deniability as if anyone breaks the law, as the seller would then also be breaking their rules as well.
I think we need to ask ourselves the harder questions of why people are stealing and figure out how to address that issue. Just like how we here tend to condemn technological solutions for social problems, tons of legal regulations can be fairly criticized for a being a legal solution to a social problem.