MFG & FSOL are certainly not dark for me..
Sandmand maybe.. From oldskool artists i would also say Toi Doi, Cydonia, Psychaos, Xenomorph, UX, Darshan , The Delta had dark edges in their music..
As for the ear-bleeding madness, well i agree it's not that dark, mostly twisted..I can't stand most of the 160BPM madness..
But have you heard to artists like e.g Para Halu ..(Album The World Of Peace , or Battle Of The Future Buddhas - Demonoizer or some Schlabbaduerst compilations or Derango - Tumult or Procs - Stuck In The Oven With Me.. I think you will like some of these.)
Many factors, probably that the scene expanded, most artists don't explore new ideas are blend with other genres.. (there are exceptions such as X-Dream maybe, or Electrypnose with his downtempo/chill album even featuring IDM)....