The UK has the stingiest welfare and healthcare systems in Western Europe but the lowest murder rate. The actual difference in the justice system is much greater surveillance and much less concern for due process and the rights of the accused than in the US. The fact that European countries can get away with shorter sentences is due to the fact that these countries actually allow these cops to go catch criminals and lock them up. Of course they also are allowed to imprison people for social media shitposts so there is a genuine trade off. Japan has the lowest violent crime rate in the world and their justice system is largely based on coercing confessions out of people and skipping the trial.