As it was, many in the French Resistance were Communists and there was a major Soviet spy ring at the time known to the Nazis as the Red Orchestra. Barbie knew their identities and key parts of those organizational structures and methods of operation. Similarly, Barbie knew who had been in the Nazi SS, secret police, and intelligence service. In the post-war era, they too were security threats because they could be recruited as potential Soviet spies and operatives or could do harm as recalcitrant Nazis.
For those reasons, Barbie was hired, used, and protected by the US as an intelligence asset. Was that wrong? Not in the spy game. And it was by such expedients that the US and the allies managed to keep Europe from falling to the Soviets or Germany from reverting to Nazism. Similarly, as a routine matter and with the approval of courts, dangerous criminals who cooperate are protected from prosecution or given lenient sentences. In a fallen world, it often happens that the only choices are between different degrees of evil.
For the Intel world, incompetence and failure is even more damaging than morally questionable methods or recruitments.
It seems to me the USA alone has a black budget of $50 billion + with very little to show for it.
Add to that the rest of the Five Eyes spending and you have huge surveillance budgets with not a lot of real successes.
That's the problem...he was "seen" as highly useful, but what useful intelligence did he actually provide this country, in order to overlook the fact that he was a freaking monster? We'll never know, because the government will never allow us to know what any of these monsters they coddled, actually did to defeat the Russians, and communism.
It wasn't until 1989 that the Berlin Wall fell, and 1991, when the U.S.S.R. collapsed. Ronald Reagan, and his policies had more to do with defeating the U.S.S.R. than any crap intelligence these animals provided our intelligence agencies in the previous 40 years. And it didn't stop the eventual spread of communism to this country. All we know is what the CIA and the other agencies have fed us over the years, and you know they would never tell us the truth about any of it.