> You don't have full control over the knife. In fact it's not about your use of the knife.
There are many knives in your relative proximity all the time. Some of them are used for your benefit, other are used for other's benefit, every one have potential to be abused against you by evil actor.
> The people in control of the knife have a poor track record at caring about you, and belong to a category that history has proven we should not trust.
Scrutiny should be proportional severity of harm times the frequency of harm.
> Every time you use the knife, you sign a blank contract giving full authorization to future non-specified knife usage to people you don't know nor do you know their motive. And you trust none of those people, for an indefinite length of time, will abuse it.
Everytime you enter restaurant or even leave your house you are giving full authorization to people around you who posses knives to use those knives for non-specified purposes. You can only hope they are reasonable and won't cause you harm.
> Cumulative use of the knife can accumulate stabs that may be delt to you and all your love ones one day all at once
Knives don't need to accumulate anything. One misapplication can end your life literally
> Use of knife can be automated and scale at the level of all countries.
There are many machines that are basically bunch of fast moving knives. It's on you to not be where they are. Their operators are bound to take precautions proportional to harm times the frequency of harm.
> Most people are not knowledgeable about the knife, don't know much about it, and it's invisible to them
You usually can't really tell how many knives are around you and most are hidden at most times.
