Abe was assassinated with a homemade gun because manufactured ones are so hard to obtain. Per capita, the rate of gun death in the US is 1600x Japan's. Hell, the total annual number of gun deaths in Japan is lower than the US's rate of gun death per 100k (~10/year in Japan vs more than 10/100k/year in the US). The US is so much worse on that aspect that it's laughably absurd you'd even make that point.
And yet a longtime head of state got assassinated with a gun. No peaceful nation has political assassinations. The people are just as violent but with fewer resources to act on that violence. The sexual assault of women is one notable projection.
Abe's assassination was an anomaly. Japan is far more peaceful than America (I'm an American)--rather than pretending Japan more violent than the US, you might prefer the more accurate argument: Japan's low crime is attributable to its strong traditional values, homogeneity, conformity, etc.
America did not ban abortion and it’s less restrictive than in Japan.
Also weird to call out shootings when a Japanese PM was assassinated with a gun less than a year ago.