I've seen a lot of people ask this since the title is so stark and unsettling. Let me clear this up: 'God Hates You, Hate Him Back' is a work of fiction by C.J. Tudgay. It's a novel, not a memoir or a nonfiction account. The plot involves a very specific and heightened supernatural scenario – the literal, physical god of the Abrahamic faiths descending to Earth as a teenager and the resulting cosmic chaos. That's not something anyone's claiming is based on true events.
What it might be drawing from, and what gives it that raw, visceral feel, is the emotional reality of religious trauma, anger at dogma, and questioning faith. Those experiences are very real for many people. Tudgay is channeling that potent, often unspoken rage into a fantastical revenge story. So while the events are invented, the fuel for the story's fire comes from a place that a lot of readers will find deeply, personally recognizable.