First of all, I think this reflects the severity of the law. The purpose of law is to maintain social order and better protect society. The Japanese Twitter killer was sentenced to death to punish the Japanese killer's killing behavior, with the aim of punishing the Japanese killer. Moreover, it can fully reflect the severe punishment of the law, make people trust the law more, praise the law more, let people know that the law should be observed, and once they break the law, they will be severely punished by the law, which can play a disciplinary and punishment role.
The second is that I think this is to safeguard social fairness and justice. If a person who kills someone is not sentenced to a heavier punishment, it is very unreasonable and does not reflect fairness and justice. The Japanese Twitter killer killed nine people, and the death penalty safeguarded social fairness and justice, but it also avenged those nine people. It also comforted the families of those victims to a certain extent, and it will also safeguard social fairness and justice, make the social atmosphere more just, and make the society more fair.
The third is that I think this is more reasonable. In fact, I think this judgment is reasonable, because the Japanese Twitter killer killed nine people, so he was sentenced to death. This is very reasonable, but also reflects the severe punishment of the law, which can make the law play a deterrent role.
In a word, I have great views on this matter, and the main points are the above three.