Because they watched a YouTube video where some guy in a dojo disarms an attacker who's wielding a rubber knife and assume it's actually that easy IRL, so cops should just channel their inner Jackie Chan to disarm the guy instead of shooting him.
Yeah, it's generally pretty easy to remain cool and collected in a "practice situation" where you know that your "attacker" has no ability nor intent to kill you, but it's a little bit more difficult in an uncontrolled, largely unknown situation where your actual attacker is charging you with a knife he intends to plunge into your liver. This shit comes from the same school of thought that brought us the Joe Biden classic "shoot 'em in the leg" among people who apparently have no awareness of human anatomy and tactics.
Magdumping, so long as you have control of the weapon and know that the projectiles won't strike anyone behind the target, isn't a bad idea. If you have drawn your firearm to face a threat, you should [and rightfully in this situation] open fire until the threat is neutralized completely. Movies and television have made it seem like "disarming shots, dissuading with a gun, disabling shots" are par for the course or something. In truth if someone is already agitated enough to be charging an armed man with a knife, you will not dissuade them even by gunpoint, chances are if you shoot for the legs/arms in an attempt to disable/disarm you will miss and be dead. Center mass magdump while backpedaling to increase distance between you and the belligerent is the best solution. Also, contrary to movies and television, people don't always instantly fall down and immediately die after being shot, and they don't immediately become a blubbering defenseless wreck at the sight of a gun either.
Assuming that you do hit the leg, that doesn't mean the belligerent will instantly go "ouchie" and stop, or fall to the ground. It also doesn't mean he won't die, because the femoral artery exists. Gunfights have happened since the first firearms. Gradually we have learned to use them to great effect and have come up with methods to increase efficacy in such situations.
It's the same stupid bullshit as: "Well, sure, he reached into his car but he didn't have a gun!" And the cop who rightfully ventilated his stupid ass isn't clairvoyant, he could've been reaching in the car for a god damn bouquet of flowers or a Desert Eagle, the question is should you bet your life on thinking "this obviously agitated individual whom we were called to deal with due to violent behavior isn't going to try and hurt me"? And the answer is no.
But it all falls on deaf ears because the retards who continuously spout this stupid bullshit won't be happy until cops everywhere are reduced to laying down and dying whenever they encounter a violent nigger, and even then they'll probably complain because the cop used rude language in his death throes that might've offended said dumb violent nigger whilst his knife was in his guts.
