Your questions are of very good quality, you don't just sweep the issue aside.
And if my friend can just tell me the debt I owe is forgiven without collecting anything from me, why didn't god just say that the debt humanity owed was forgiven without having to sacrifice anyone in the process?
that's a good question, for instance.
1/ God might not agree to do without a compensation. This is at least how Matthew 20:28 might be interpreted or Hebrews 10:26.
2/ Jesus did agree to die without receiving any compensation from humankind.
Seems odd.
But that's how it might be, in my view. This is at least how the whole story could make perfect sense, in my view.
One comparison:
At a point in my life, I couldn't pay rent.
Sadly.
My landlord did not cancel the debt.
But a friend of mine from the church I attend offered me to give me some money so I could pay the last 2 rents.
I was enthusiastic about it.
Know what: my friend gave me the money - for free.
That was a great experience.
But my landlord was a good guy also.
He just happened to want to have the rent, which is totally fine.
You see: two good guys: the one said I want the rent, the other said I pay it for free.
This is how different good guys can be at times.
By the way it was a great feeling to receive help like this. After this, God made it possible that I could pay rent every single time.
I don't see how that changes anything. The message remains the same: If you want god's forgiveness, someone has to die.
Here, you raise a point that
@1213 evoked already.
Forgiveness
for the sins can be free. This is what 1213 has explained well, in my view.
Compensation
for the damage might not, as Matthew 20:28 shows that there is still compensation that needs to be paid.
This is how I read this verse, at least. It is not about forgiveness of sins.
But what kind of a being would consider killing his own son as valid compensation for anything? It's sounds completely illogical to me.
But how did Jesus dying, at least for a couple days, do anything to clean up the rivers?[...]And for some reason killing his own son somehow makes him feel LESS sad about the polluted rivers?. None of it makes any sense whatsoever.
If Mankind would have given him a bunch of flowers in return... an God feels less sad... which I doubt, I mean just in case... then that's the way it is. Even if the rivers don't get cleaned up by the bunch of flowers.
However, bunches of flowers can make people less sad, at times.
Even if they don't clean the rivers up.
My point is: the moment God says he regards the compensation as paid.... this is how it is and the debt no longer exists.
Moreover, my point also is Jesus's death does have a true value for God, for it set an example that all future martyrs that are killied just for being Christians could study.
So, this does have a very practical benefit for God.
Even if this does not refer to the rivers, in detail, but... it's not only the rivers that are polluted.
At this point you may ask: how does this death address pollution in general?
Well, Christianity criticises greed. And greed is often what produces pollution (since polluting makes great sense economically).
But if the first Christians who promoted their new stance against greed... almost always got killed, these at least have a good story to read in the Bible about Jesus getting killed, too.
EDITED to indicate that this is how it might make sense. Maybe there are other factors that I don't see that would make perfect sense also.