I think "tough love" is the basic idea of cruel kindness -- making someone do something really hard which is for their own good. So, for example, you could say:
The drill sergeant forced them to run every day until they dropped, so they could build the stamina they would need in combat.
Fiercely peaceful brings to mind Gandhi and Martin Luther King, who were fiercely committed to non-violent protest. An example sentence might be:
The protesters were fiercely peaceful, holding their ground despite being sprayed with water hoses and showered with tear gas.
A human robot would be a real person whose behavior is robotic. For example:
In the early days of assembly lines, human robots did exactly the same small task over and over again for hours on end.