Civil servants do not get a cut of the money from the auction; that money goes to the Treasury (or to some general fund for the public good).  They are motivated by gold stars in their resumé, that eventually lead to promotions.  Catching and convicting criminals yields gold stars for all involved.  Carrying out a smooth auction of a weird item, with no complaints of bad press,  also yields gold stars.  They do not care if the auction messes the market or gets a lousy price, but they worry about doing something stupid that could stain their resumés -- such as auctioning a bunch of seized game tickets after the game, or auctioning so much stuff at one time that they cannot get enough bidders for it.