You were brilliant, I think, but consumed by the inevitability of the abattoir. In your fiction, all the gates are closed; characters are funneled down a chute to flashing knives. In your best fiction, the characters know what is happening, but the knowledge makes no difference; there’s no way out.
You didn’t believe in the possibility of escape. Assuming the nom de plume and persona of James Tiptree, Jr., meant at least you could step outside the chute and be the one wielding the knife. As Raccoona Sheldon, on the other hand, you were bound — as were we — inside the doomed and running cows; then you sometimes tantalized your victims with a vision of a better reality before tearing it to shreds before our eyes (“Your Faces, O My Sisters! Your Faces Filled of Light!”), and sometimes you focused unwaveringly on the stark machinery of death (“The Screwfly Solution”). But for you there was no way out.