There is a lot of literature out there including on Wikipedia, but the best resource is probably the memoir written by her daughter, detailing how hard it was to live with stigma against her mom, etc: https://www.amazon.com/Living-Gloria-Films-daughters-memory/dp/1906254028
The Gloria tapes existed before we realized how incredibly harmful this was. Gloria gave consent because she had no idea how her life would be affected, how her daughter's life would be affected, by this. Luckily we now know the harm this can cause (see the book by Gloria's daughter for a first hand account of the harm caused) and therefore it is now deemed unethical to ask someone to consent for public displaying of their therapy tapes.