Malefic was quite unhappy with Moribund as well. Apparently not getting much money at all despite what must have been really good sales. Regarding Southern Lord, I guess he didn't feel like he was fairly compensated for vocal work touring with Sunn 0))). I don't know how much he could have expected to get for that anyway. Although he's a strong live vocalist, I doubt he had that much impact on ticket/merch sales.
I think part of what looks like Xasthur's prolific release output is an attempt to get out of that contract as fast as possible, hence the many releases in 2004, and those releases having a fair amount of rerecordings. This somewhat validates the sameyness complaints about Xasthur releases. There's a good chance he was just trying to rush them out. It's most obvious with To Violate The Oblivious. The material on Subliminal Genocide was way better. The material on the non-Moribund splits is also really good.