On the theory side of things, i agree, moderation is not simply closing a thread, that has gone offroad. There are rules, that have to be uphold and enforeced, and depending on how much room the mods have for interpreting and enforcing, they can cleanse more or less.
However, on the reality side of things, that would require an actually operational mod crew, that has enough manpower to do the job. And since a long time, i have the feeling, that the mods here are way more rare than a legendary pokemon.
If they simply don´t have enough people, then at least for me, it´s understandable, that they rather close a thread, that became a flamewar, than trying to clean that mess. Desireable? Nope. Understandable? Unfortunately yes.
… spider…