Presumably, this delightful word parses to "beating a dead horse", or more precisely, "loving to inflict pain upon dead horses".

Many cliques and sub-cliques within a large group (The Fandom springs to mind) have nothing better to do than rehash the same discussions over and over again. Actually, that's not true; often a kind of equilibrium is reached, but then somebody new shows up, and they must be thoroughly indoctrinated using a series of discussions and arguments so worn-out that they belong in a thrift store.

Although I imagine that everybody has bouts of sadoequinecrophilia now and then.