Allow me to tell my story--it will take but a word or two. I passed through your town at a certain time, and received a deep offence which I had not earned. Any other man would have been content to kill one or two of you and call it square, but to me that would have been a trivial revenge, and inadequate; for the dead do not SUFFER. Besides I could not kill you all--and, anyway, made as I am, even that would not have satisfied me. I wanted to damage every man in the place, and every woman--and not in their bodies or in their estate, but in their vanity--the place where feeble and foolish people are most vulnerable. So I disguised myself and came back and studied you.

上面节选中：Any other man would have been content to kill one or two of you and call it square, but to me that would have been a trivial revenge, and inadequate; for the dead do not SUFFER. Besides I could not kill you all--and, anyway, made as I am, even that would not have satisfied me.

1) 这些情态动词都是表示推测，而非虚拟用法吧？

2) 为什么是Besides I could not kill you all， 而不是Besides I could not have killed you all?

这里是对已发生的过去情况推测，所以，为什么不是不是Besides I could not have killed you all?

麻烦老师深入讲解，非常感谢！