In a fucked up way, I understand the *idea* of what this guy is getting at.
You have 700,000+ LEO's out there that might need to use deadly force some day. At some point, you want someone to train/address them on that possibility, so that they can act when necessary without hesitation or fear, because it might mean saving innocent lives.
So you take the angle "killing someone isn't that big of a deal, really," and try to make them feel more comfortable with the thought of killing another human. The thinking is that it's going to put them in a more reasonable state of mind when it comes time for them to pull the trigger on a bad guy, rather than hesitating and being scared of the personal/moral consequences.
You don't want a cop paralyzed by the implications of killing someone in the moment, you just want them to act.
The problem is that this guy swings the pendulum waaaaaaaaaaaaaaaaaaaay too far in that direction, rather than trying to balance the idea of "killing someone may be necessary, and you need to be ready to do so," vs "killing someone is no big deal at all"