Well, a complex question with a complex answer. You say now, not so Charles yet it is true. It is like describing the complexities of self defense and that in my view is the crux of the issue. This may apply to all perceptions as to weapons and legalities.
First, it is about perception. The laws are often created due to misconceptions by society. This is fed by media manipulation. The way the news depicts things, etc. that are from ignorance and a lack of effort to truly seek out truth and knowledge. It is as natural as anything human, we just do this stuff naturally.
Second, if society perceives it as an aggressive tool for doing violence then it will hardly ever be allowable for use in self defense or self protection. Even if in the home it can be perceived this way and result in prosecution and jail. If you have the ability in your home to run your obligated to do so within unspecified parameters and if you use some weapon then how you use it and when you stop using it can change home defense into violent aggressive attacks against that poor defenseless son of some family who say he was such a good boy who just happened to go astray type thing. Think I am kidding, they used stories similar to these in the NRA magazine, when I was a member so long ago, to get laughs, etc.
In California it took just one incident that made the news, as if often the case, that inflamed the general population into perceiving such things as shuriken, nunchaku, etc. as deadly weapons so they became illegal. It is the way humans work at all levels. It is how misperceptions come about and it is life so live with it.
Do you really need those weapons and do you really think that society, even if not illegal, will allow you to use them in defense? If they did, don't you think that how you use them, when you use them and the perceptions of that usage are going to most often lead to charges, trial and conviction?
This just begs the question as to why all this stuff is not discussed and taught in most self defense training models. I guess it is just plain dumb luck since about 90% of all SD trainees and graduates will never, ever encounter such situations requiring SD actions.
Avoidance and deescalation, etc. are the true fundamentals of self defense in my view. So, in closing, if weapons are made illegal then think outside the box on how you can avoid violence and if you can't how you can deescalate it and if you can't then how you apply self defense appropriately to not get too much damage, to escape quickly and to not get charged and convicted of fighting or violent conflicts, etc.
Come on everyone, think about this stuff. Ok, off the soap box!