Isn't is possible for someone to stab you? So in theory you could have some small degree of worry about your safety. Different people have different places they draw the line for an acceptable amount of worry vs an acceptable amount of freedom restrictions.
In (most of) the EU, it’s illegal to carry a weapon of any kind unless you have a reason to do so (ie, going hunting). You can’t even carry pepper spray.
To take it to the extreme, the law could force you to live in a little cell locked away from everyone. This would prevent you from being stabbed by someone else (except one of the guards).
Like I said, there's a tradeoff between security and freedom.
(As opposed to gun control.)
Use of it should constitute assault, which gets turned into legitimate self defense in various situations, just as if you were hitting someone.
Some of those bans and laws are just reasons to jail or fine people and do not in particular help with safety. After all, anyone can have a knife or martial arts on them anywhere for legitimate reasons, and you better have means to defend against these.
If you don’t want to be vaccinated or pay your taxes, you are, on some level, a danger to society.