Think of it this way: Systems vs Demographics

We as a society should never condone a system (government/CEOs/billionaires) killing a demographic (individual or group), like the death penalty. Because the system already has greater power and control.

However, the demographic should be able to kill or dismantle systems, especially when they feel threatened by those with power.

So "the people" can take the lives of the rich into their hands, but the rich can't take the lives of "the people" into their hands. Ideally.

Which is why it's okay to be pro assassination of a CEO, but not pro death penalty of a serial killer. Government (system) sanctioned murder (of a demographic) should never be okay.