I suspect most Tor exit nodes are controlled by the US government and/or its allied governments. It doesn't make much sense for anybody else to run an exit node because your IP gets banned by much of the internet and you get unwanted visits from law enforcement.
"What kinds of people operate tor exit nodes and why do they do it" is one of those questions that I know I'm not even supposed to admit being curious about, let alone ask, in the company of people who are most capable of accurately answering.