Of course we need to defend ourselves from evil actions - but if more people followed the teachings of Jesus there would be less need to defend ourselves.
But the point is - who decides what actions are acceptable and which are unacceptable.
Given that you have clearly indicated that you'd vote to retain a ban on assisted dying. And presumably you'd still do so if by some weird quirk of fate you were the only person who turned up so the decision would be yours alone. And were assisted dying to be made lawful can you confirm whether (if you had the chance) you'd vote to make it unlawful again.
On those assumptions the answer to 'who decides?' seems, in your opinion, to be ... err ... you. Yet you still claim not to be restricted others choices nor to be imposing your views on others.
Now, don't get me wrong - I think there are times when a society should place restrictions on others. I gave an example of speed restrictions. I support them and I'd vote in favour of them were I given the chance. But I am honest in also recognising that were I to do this I'd be restricting choices (in this case to drive at any speed on likes without risk of sanction) and I'd be imposing my view on others. But I'd consider this to be legitimate rather than disingenuously claiming not to be restricting choice nor imposing my view on others.