I hope you realize that is a tongue-in-cheek characterization. These men envision (hence, visionary) for themselves a grand place in the history books. On their way to trying to carve that place they leave behind great, unthinkable harm. As was true of Mussolini and other 'visionaries' the harm they cause is immaterial to them, of no consequence. These leaders have grand schemes. What matters the individual in that 'vision'?