All that bog gas has turned your brain to mush mate, I don't know how much simpler I can make this for you? Lol
Whether harsher sentences deter knife crime is up for debate, what isn't up for debate is a longer sentence offers a criminal less chance to reoffend, that is undeniable.
I see you are ducking & diving again, genetic inheritance. Glasgow, a city once labeled the murder capital of Europe saw massive improvements in murder and violent crime rates. If Glaswegians are genetically predisposed to commit murder, how did things improve?