Not so many years ago, a cop could go an entire career, and never draw his sidearm outside the range. That's not so today. When I was in patrol, I can count on one hand the number of weeks that I didn't have my gun out for some reason. In my current specialty assignment, it varies more. I have some weeks that I've got it out several times a day; I've got other weeks that I don't need it. But, beyond not drawing it unless it's reasonably likely that I may need it -- in other words, drawing to show off or other forms of mishandling -- I don't have to justify it.
A police officer is indeed given wider latitude to do what would be considered brandishing a firearm than an ordinary citizen -- but that doesn't mean that an ordinary citizen, in a situation where they may reasonably percieve that a person is likely to present an immediate threat of bodily harm to themselves or another person may not draw a gun or otherwise prepare to use force. (By the way, if a cop with no justification threatens to shoot someone, or uses any unjustified force -- they are civilly, criminally, and administratively liable.)
If a private citizen uses lethal force, be that a gun or lethal (that is, likely to cause serious bodily harm or death) blows, they must justify just as an officer would -- but they may well be given wider latitude in using more force than an officer would!
The techniques shown in the video clip represent a range of force, including lethal force. Justification for the use of that force may be different in Japan (and is addressed in the clip), but I was simply addressing a widely misunderstood issue about police use of force in the US. Quite simply, many people think that a police officer must use MINIMUM force -- and that's not so. Many people think that a police officer's use of force will be judged by an objective standard; it's not. (See Graham v. Oconnor) It's a complicated assessment of the reasonableness in light of the total circumstances present, including the officer's relative fitness and ability, the suspect's capability, and the environment. It's not a tit-for-tat, "if you punch me, I can punch you" thing. Instead, the officer is permitted to use the necessary force, which may exceed the resistance encountered, to defend himself (which is also true for a private citizen) or to effect an arrest or otherwise take control of a person (which is not true of a private citizen, outside of very narrow issues of citizen arrest, which you are strongly advised not to even begin to mess with; it's too easy to go very wrong!).