Why? This is a canonical piece of technology that nobody has had any issue with until now. If it was such a bit issue, than the factory admins would have banned it as a superweapon. As it stands, it has not been banned. Now while I personally disagree with some things in regards to technology being banned, I can understand why such things are banned and do my best to work beyond it and try to introduce something unorthodox instead that fits within current lore/canon.
This 'midichlorian killer' as I'll call it, cannot truly hurt anybody...because we all choose how much damage we take. We have people surviving being decapitated on site by lightsabers, all of this because we choose when our characters die and what damage they will take. So something like this midichlorian killer is just a fancy tool that has only recently come to light because of new submissions. This very thing. This can be a great plot device, take shooting a jedi on the level of a master and they lose their connection to the force temporarily because of this weapon...you have a greatly intriguing story that is very investing.
As [member="Tanomas Graf"] has mentioned, we have far greater weapons at out disposal than just this disruptor. We have nukes, we have mini death-star lasers, we have mass cloned armies of force users (probably), all things that can be perceived as more powerful than a simple gun that can disintegrate people.