Now I feel like telling your T, "give captgut a candy every session please!"

Capt, trauma has long lasting effects whether you've a genetic predisposition to psychosis or not.

And yes while psychotic disorders do have a partial genetic component similar to anxiety and depression (the other part is environment and life experiences), there's quite a lot of research on how ongoing trauma can make someone genetically disposed to psychosis have higher likelihood to develop it.

Many people who hear voices and who've been abused hear their abusers or hear threatening voices

(sorry I don't know a lot more about trauma and psychosis and I wish I had all my sources to link you. Here's one:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5054510/ )

And true, I don't know the details of what you experienced, yet I also don't need to in a way. What's enough is that you were abused by a family member and then blamed by your family. Doesn't matter if it "just" happened once, that's one time too many, and repeated incidents just makes it worse.