I haven’t read anything about him criticizing Stalin or Trotsky but he wrote a great deal expressing his hatred for Hitler. He was a democratic socialist but it’s paradoxical because he said “It has always been obvious that a planned and centralized society is liable to develop into an oligarchy or a dictatorship" From this quote and some other statements Orwell made it seems as if he understands socialism and planning will lead to totalitarianism, the same kind he appeared to be so fervently against in 1984 but he still went on to propose the nationalization of all major industries and central economic planning.