When your experience with someone has only been positive like you just decribed, it doesn't feel right to participate in negative talk or to decide he is bad without seeing things for yourself. Even worse is when someone expresses that kind of rage directed at you, that tends to put the spotlight more on the person now hurting you as showing the bad behavior. So the only evidence you have of bad and toxic behavior is coming from your friend. And, she did that at a time when you had major challenges yourself taking place. That was pretty selfish of her.

There have been times when I helped someone else when I was genuinely experiencing something bad myself. I should have seen that red flag as a sign too. That my problem did not matter and this individual wanted to use me. I later found that out once I expressed a boundary and watched the person not only put me down, but proceed to rage rant about me in a smear campaign. And that took precedent over anyone else needing help for THEIR challenges.

I know you want to write an angry letter, however, when someone doesn't respect your boundaries typically they will just use that letter to say you are the bad person and they are the victim. You did the right thing in getting therapy and even sharing here too where you got to vent things out Dechan. When someone chooses to hurt you it's important you say ouch with someone who can see you are hurt, and not with someone who wanted to hurt you enough so you would say ouch. There is nothing wrong with remembering YOU were a nice person either. It's ok to walk away from someone carrying a sword and choosing not to engage in their toxic dual. That list you wrote out in your post was important in that what you shared means that any angry letter you write will not make any difference, when a person doesn't care and wants to hurt you, they will decide an angry letter is only a win for them.