The thing about DBT, especially in the group setting, us not designed to address the problems or traumas that brought you to therapy in the first place. It is all about interpersonal relations and distress tolerance. In short it is to give you the tools you need to help you navigate through life in a way that feels healthy and productive. If you need to do more specific, deeper work, you need individual therapy as well (most people in DBT groups that I've run are in therapy). I have never been to one, observed one and hopefully not run one where people feel invalidated. It's possible that the group dynamic is not a match for you and in that case Id find another. I hope you can find another method that helps you more.