When someone says something invalidating such as that, it shows me they lack understanding. I use that as a sign they aren't the person I should go to anymore for validation, compassion, or support because they are unable to give it for whatever reason.
Yes, I could choose to use my energy fruitlessly trying to change or educate them, but I want all my limited energy to be used on healing.
I seek out people who do get it, and the rest I now choose to allow them to just be as they are. I don't seek anything further from them. Perhaps they are a good book friend, or someone to go to movies with. Or maybe they're a family member who can best be tolerated by keeping the conversation light. So, I steer clear of topics which have proven to be unhelpful in creating a healthier interaction pattern.
I refuse to use up any more of my time on this earth trying to get my needs met from those unable or unwilling to do so. It caused me so much heartache over the decades. Now, I have a few people who absolutely just "get it" and I can just be me with them.
Once I know someone doesn't get it, every time I choose to try to get validation from them, I'm choosing to set myself up for yet another abandonment situation to re-traumatize me. For me, it was a form of self-harm to keep doing the same thing and expecting a different result. I had to escape my family of origin and build a life for myself without their help, because the only help they were willing to give was so toxic it was literally killing me.
Now, for those who are not my friends who get it, I share just a part of myself. I don't have to share more. Doing so ruins the strongest part of our relationship, which usually is a shared interest other than my problems, such as board games.
It's taken me a long time to stop being me as "all PTSD, all the time." That didn't help me widen my circle of friends and acquaintances, as it wears all human beings out eventually.
It didn't bring allow me to creat comforting, sustaining memories in my current life. I kept bringing the traumas of yesterday into every experience, allowing my past abusers to keep stealing my life from me again each new day.
I refuse to allow them to do that to me anymore than what just happens. I can't stop the re-experiencing, flashbacks, triggering that occurs. But I have tools I can use to deal with it effectively to get right out of it and back to the present as soon as possible.
I have set times with my therapists and sufferer friends to handle my PTSD. The rest of the time, as I can, I'm trying to build a life worth living today, and worth remembering tomorrow.