at times I still get those how and why questions, stuck in there
I'm going to be direct with something, and I hope you do not take it as anything but what it is: a desire to be helpful.
Something I learned is that I needed to be strict with myself when my mind was going down blind alleys, or getting stuck on upsetting things. When it comes to these kinds of thoughts - trying to puzzle out the "why's" - these thoughts are things we actually have
full control over. Even if we think we don't. As long as the thought is happening in the here and now, and not as part of a flashback, we can change the thought.
In mindfulness, it's called "turning the mind" - literally, you turn away from that thought that is only going to cause you harm, and you put your mind on something else. It takes a lot of discipline, and sometimes I find I have to turn my mind many times in the span of even 5 minutes. But still, I do it.
Sometimes we actually want to feel the pain of painful thoughts. I say this as a person who knows - it can feel good to feel something, anything sometimes - and so it becomes easy to ruminate on the common painful thoughts - usually "why" type thoughts. I'm not saying that you are doing this to yourself on purpose - though you should talk with your therapist about the idea of clinging to the pain because it is familiar, because a part of you might be - the main point is that you are
always able to change a thought. And when you change the thought, the feeling will change also.
It takes practicing, and discipline, and there are some thoughts it is hard to look away from - for you, I see a theme of "why did they do this, why aren't they being punished, why should I have to suffer for their wrongs". The fact is, there is no answer, only a corresponding feeling of sadness, helplessness, desperation.
Feel the pain or grief you need to feel, if you need to feel it; but then, turn your mind. And sometimes, it's not even that we
need to grieve - it's just that it's what feels familiar. It won't stop feeling that way until you can stop returning to those thoughts regularly.
All this is only my opinion, of course. I've just found that (for myself) it is better to step away from the questions of "why" and the pain that goes with them.