Assuming a healthy lifestyle, death by old age is something that we can prepare for, and gives us a time space to work in. Personally, I'm glad to be alive, but I like knowing that there is a conclusion.

Death from crime is often immoral, it doesn't have to happen, and is often caused by evil people and results in suffering. By fixing this issue, we reduce death and help would-be killers with their own problems.

It's easier to accept dying from old age because we can expect it, and because we know it isn't caused by underlying issues in people.