I understand your anger and I've felt it before too. But, recently I've felt much better about keeping my PTSD to myself. Here's what's changed.
I decided that people communicate with each other for a purpose. Others accept emotional input from people when it is relevant to the present time, but after that they want to know why you're telling them. Is there something you want them to do about it? Is there something you could do about it, if only you had the right advice? Do you want sympathy? Are you expecting to be treated differently? These are the things people think of when they're told about painful experiences, IMHO.
So, I wonder to myself... do I want them trying to solve my symptoms for me? No. I don't want to be treated differently than other people because that strains my relationships. People have to consider all my nuances before speaking, and that's a lot of work - and they'll tire of having me around. People glance sideways at me if they know something is a trigger for me. It's not mean, they care... and they want to see how I'm affected, if I'm okay, if I'm going to explode or whatever. So, I don't want them knowing more triggers than they figure out by interacting with me. It wouldn't matter if they knew WHY I get angry over X, or that it's justified, because the end result would still be the same. They would still look at me when they think something is a trigger for me. Ugh, that's embarrassing.
I think this all comes down to boundaries. For me, it's all about realizing that the level of intimacy that I'm used to and want from my relationships is codependent. It's not healthy, nor is it possible for anyone to know me as well as I feel like they do when we've bonded so deeply. They are still outside of me, other than me, different people... and they have their own thoughts about our experiences which sometimes differ from mine. The good thing about this is that accepting that they're different helps me accept that I am different. I don't have to be a clone of anyone to assert my opinions, respect myself, be proud of who I am, and make my own choices. When I think life is too overwhelming, I think about those four self empowering principles and suddenly the weight of the world lifts off my shoulders. If I can give that to myself, then I can survive whatever negative I fear will take place in my social circle.
It was a painful grieving process when I started changing my core belief on what to expect from others, but it empowered me to expect myself to understand others less and understand myself more. I am my own best friend, confidant, rock. It can be lonely, but then I turn my focus toward others and see that they want the support that I want, and supporting them feels like I'm getting support too. It's weird how that helps me as much as it does those I'm offering support to.
I hope this helps you better perceive your decision to choose with whom you will share your different life experiences. There are topics which I do not discuss here, at all. I don't share them because they would be too telling about my identity. You don't have to hide the PTSD and trauma in a shameful box when you're out in public. Instead, you protect yourself and you honor yourself by choosing to share it with people who are safe and have the capacity to understand and give validation. It is a self-loving choice, IMHO.