Because the moderators would get accused of bias for only deleting Balrog666, js1138, Jaguarbhzrd, Dimensio, freedumb2003, atlaw, and b_sharp posts. These are the ones that mount the shrill, crazed, and relentless attacks on a particular individual, in an attempt to get them to post something that will get the victim banned. This has gone on for 8 years here, and the only answer to it has been the "smokey back room."