The tl;dr version: God is a Magic 8-Ball, humans are at fault for why bad things happen, but God loves us anyway because humans band together when bad things happen. Oh, and don't bother asking for things you want, God will tell you what you really need once you start believing in him.
Pretty much typical Christian rhetoric, answered dozens of times, yet each new Christian brings it out as if nobody here had ever heard of it.
I don't have time to write a long, detailed response to this letter, but here's a major flaw in the overall argument that I doubt most Christians have even considered. Specifically, punishing descendants for the actions of their forebears. Let's say you have a man and woman who were thieves, then settled down and got married, had kids, etc. Then someone caught up to them , and instead of just punishing them, punished their children as well. And then their children's children, and their children's children's children, and so on. Not just once, or twice, but every day of their lives.
It isn't just that the punishment would be unfair and unjust. It would actually cause people to rebel, to fight back, usually by doing the very thing that they were being punished for in the first place - the punishment would cause the behavior it was designed to stop. In other words, this claim that Adam & Eve screwed up and thus all humans deserve to be punished the same way simply ensures that the same behavior will be repeated.
In other words, YHWH's approach was catastrophically flawed, and it took him thousands of years to figure it out. And his revised approach hasn't exactly worked all that well, since Christians are even more prone to bad behavior than atheists are. Both approaches depended on humans doing what they were told and not thinking for themselves - in essence, the same approach that he tried initially with Adam & Eve, and which hasn't ever worked in the long run.
I guess YHWH just isn't very good at dealing with free-willed beings.