I don't think the non-card market is particularly plagued by constant listing and delisting. It was an issue with the rental market years back when the bots were constantly relisting hundreds of thousands of 1 bcx cards. 19k average listings seems like it should really not be a big deal with regard to server costs.
So in the absence of fixing a problem it rather seems like a small tax, to which I say, if the DAO wants more taxes then just dont burn the ones you get.