Death-by-person probably less controllable than death-by-equipment-failure. But, in reality, I'm not sure that it is. There are processes/procedures to reduce the likelihood of both.

This is exactly what I'm struggling with. Intuitively, the idea of another person trying to injure me sounds scarier than a harness failing or tree falling. People can be a lot more unpredictable than gravity or metal fatigue. But then again, the safety of loggers and roofers depends not only on their own gear & diligence, but also on human co-workers who can be just as unpredictable. Versus violent criminals, at least the co-workers aren't actively and creatively malicious (usually).

The actual homicide rate of cops is almost half of the normal population.

Interesting. Do you have a link? Those numbers are hard to Google, all the results I'm getting are for deaths caused by the police vs. of police themselves.