That’s completely valid. I’ve done plenty of trauma dumping here on Lemmy. 99% of it about my ex wife and the shit she’s put me through (massive debt, constant manipulation, threats of suicide, making me feel guilty for literally everything wrong with the world, etc).
Sometimes you want to vent to someone, and you don’t want it to be anyone you know. Plus therapy can be expensive (even in my country despite having socialized healthcare, because all the therapists that work with the socialized healthcare system are booked until the next quarter after the end of the universe usually)