Did she say "self-righteous indignation" or just "righteous indignation?" Because definitely "righteous indignation" is the more common expression by far.

Just checking because sometimes I have a way of distorting what I hear in therapy. Once my t said she was angry FOR me but I heard that she was angry AT me and I was very distraught and within seconds had a whole story in my head about how much she thought I sucked... I was very relieved when we clarified that. So maybe ask your t to clarify.

And if it turns out that she does think you're being self-righteous you can tell her that you feel that's a huge mischaracterization.