It would bother me. I might feel defensive and angry, and hope he could find a more helpful way to communicate next time. I would consider though that in a therapy group, it's just part of the process to receive (and give) feedback in front of the group. And then maybe I would consider there was likely some truth to it and try to work that out going forward, because I think often the comments that hurt the most have a valuable lesson in them. They show us areas where we're really sensitive and might have a growth opportunity.

Sometimes when my therapist has made powerful suggestions like that and tried to help me consider my options, I have reacted, but come to see the value in her perspective. It sounds like he was just iterating some of the key, well known DBT techniques, so he may have expected you to be open to them as they are part of the traditional DBT playbook and your therapy group is a DBT one if I remember right? I hope he gets back to you and you two can come to peace on this subject and find the techniques that will work best for you. It's one thing to say you're resisting techniques that might help you, but then the real work is to figure out why and what to do about it.