You have begun to discover how tangled life is. In your current situation, most of the trouble is that history is written by the victors, not the invaded. If Germany had won WW II, the history books would still say that it began with Poland invading Germany, rather than with a false-flag attack. Then, parts of the official history are trumpeted while most is forgotten. You have heard of "The Holocaust" but you probably don't know that, as holocausts go, it was pretty average in both numbers killed and in percentage of a population. There have been hundreds of others in history, but all the others combined get less publicity.
The people you want to write about are psychopaths, an incredibly slippery group. One scientist studying them would even visit convicted criminals, and be temporarily charmed into believing their lies every time. They consider themselves above human morality - they can trick normal people as easily as we catch fish.
So, I think your frustration is mostly realizing that addressing your topic requires getting out of a small shell and exploring a vast world, instead of describing a few impressions from inside.