Some sellers do not answer questions because they can get auto 5 stars for communication if there is no two-way communication between the seller and the buyer.

What the....?   In what world is good communication defined as no communication at all?  Why would Ebay grant automatic five stars for communication for NOT communicating with buyers at all?  This defies all logic!  Do they honestly think that any two way communication is an indicator poor performance issues?  They really have lost the plot!