WHY was Jesus cricified?

[John V]

Is it just to torture someone eternally for the small wrongs of their life? ----I don't think so.

Do people go through life only having committed small wrongs? -- I don't think so. Note that God judges the thoughts as well as the deeds. This principle is throughout Scripture. Before the flood it was noted that their thoughts were evil all the time. The law prohibits coveting. There's no punishment given for it as we can't read each other's minds, but God knows our minds. Jesus likewise equates thought with action in the sermon on the mount.

Is it just to either victims or society to allow someone other that the perpetrator to go to jail for the perpetrator? ---- Try floating that balloon in the court room and see how the public would react.

Is it just to punish sons for the sins of their fathers (or great, great, great, great. . . . grandfathers)? ----It is not.

Who are these people without sin of their own?

What you are saying is that god has a completely different standard of justice

Not completely different, but yes, substitution is rare in human justice systems. Part of that is preventative - we don't want a criminal back on the streets. But, that doesn't apply in Jesus' case.

and that by his very nature he can't violate that standard of justice.

Yes. I don't see why this part is controversial.