Why MIB and Jacob test human souls by Jerry Williams

I will try to explain what I think is the sense of all the 'game' between MIB and Jacob. In recent episodes it is suggested that they both were normal people (or at least MIB was). Ok, now let's suppose that they ended up in the Island by chance and that in the Island there was some kind magnetic power that gave to Jacob and MIB the strange supernatural abilities you all know.

I have the theory that MIB was somehow 'infected' by its powers, causing the destruction of human souls if they take contact with him. The point here is that maybe Jacob pushed MIB to that state, and he did it not on purpose. Let me explain: imagine that young MIB and Jacob, trapped in the island, started an argument and in the fight MIB falls to a pit/hole/strange place were he gets 'infected'. An then (or later on) MIB and Jacob receive their powers.

What's the situation? The point is that Jacob is really sorry for being responsible of the MIB 'infection', and he knows that letting MIB go out of the Island would mean the destruction of humanity. A destruction that may not be physical, but more spiritual or methaphisical. So Jacob is morally forced to prevent MIB from leaving the Island.

On the other side, MIB gets angry with Jacob for what he (inintentionally) did to him. Anyway, he wants to leave the Island, even knowing that it would mean the (spiritual) destruction of humanity. Why is not MIB morally sensitive to that disaster? That leads to the following point...

MIB thinks that, in the end, it's not his fault. Was Jacob who (unintentionally) 'infected' him, so he doesn't want to be responsible of its new dangerous state. But the most important point here is that MIB thinks that humans are not good enough to be redeemed. "Why should I care about humans souls if they always corrupt and destroy? Why should I care about their souls?" But Jacob thinks that humanity is inherently good, so he has the debt of protecting them from the monster he helped creating.

And that leads to the final point. If MIB convinces Jacob that humanity is bad, then he could go home out of the Island. On the contrary, Jacob must convince MIB that humanity is good to justify the fact of keeping MIB trapped in the Island. To deliver the goodness or badness of humanity Jacob brings people to the Island. MIB, in order to prove Jacob is wrong, has to kill them all indirectly, corrupting them and moving the proper strings to make them kill each other.

This is the reason MIB and Jacob are making their experiments to prove the goodness or badness of humanity. Jacob feels responsible of MIB infection and wants to protect humanity because he thinks we are good, but MIB just wants to be free and doesn't care about the consequences of leaving the Island because he thinks humanity is bad and unworthy of any consideration.

Maybe I am completely wrong, but I think that the two main points are that Jacob is directly responsible of the MIB state and that MIB leaving the island would not 'destroy' the world in a literal sense, but in a spiritual one.