He was a good man and he meant well. And the mess the country was in was not his fault. Such a shame that he was completely ignorant of economics and so allowed himself to get so thoroughly duped by Douglas.
Ignorance doesn't excuse everything, though. At some point a genuine left-winger ought to be able to recognize when policies are screwing over the people they're supposed to stand for. HP.
He did eventually recognize it, but by the time he was able to take action it was too late. Most of the cabinet were strongly supportive of Douglas' policies because they had worked for awhile, and if you're familiar with the situation in NZ when Muldoon was ousted, you'd see that he had basically had a stranglehold on the economy. Douglas' policy was to free it up (which WAS necessary). Lange and others all believed in that... But Douglas basically used the situation to go far beyond what was necessary. The problem was, Lange was partially occupied with foreign policy and did not realize until 1987 just how dire some of Douglas' policies were. It was then that the two basically engaged in open warfare, but Lange couldn't win because cabinet was made up entirely of people who thought Roger had the answers. When Lange sacked him, they voted to re-admit him. That was it for Lange.
I generally feel he was in the right through the situation and I think he realized it too late.