The paradox of benevolent deception is that doctors used to think that it was okay to not tell patients things, especially if they were poor and black.
A paradox is two contradictory words. Benevolent implies being good and caring, but deception does not. Deception is tricking someone. Doctors in their hubris seem to think that they know what is best for the patient, regardless of how the patient feels.
In the 1950s when Henrietta was dying of cancer, it never would have occurred to her to question her doctor. She told the doctors she was not cured, but when they sent her home she went.
This was a time when “benevolent deception“ was a common practice—doctors often withheld even the most fundamental information from their patients, sometimes not giving them any diagnosis at all. (ch 8, p. 111)
Doctors did not want to frighten or concern their patients by giving them information. The doctor knew best, and what the patient did not know could not hurt her. Of course, a patient cannot make an informed decision about their care. No one questioned doctors, “especially black patients in public wards” (p. 111). Henrietta did not know that her patients took some of her cancer cells. She did not know what they were planning to use them for. She never could have imagined what would end up happening to them, or how important they would become.
It's certainly true that the term "benevolent deception" is self-contradictory. The paradox of benevolent deception is that it isn't always benevolent or humane in actual terms. It gives false hope to a patient who has little chance of recovery from a fatal illness.
In the 1950s (before the modern era of "informed consent" in the healthcare industry), doctors routinely deceived their patients about their diagnoses. Many of these doctors took to heart the Hippocratic oath to "first do no harm"; they had no wish to confuse or frighten their already vulnerable patients with full disclosures about their illnesses. Henrietta's doctors deceived her because they believed that it was the compassionate thing to do; they had little expectation that a black woman would be able to comprehend all the ramifications of her illness, and they wanted to protect her from further distress.
In doing so, the doctors waived Henrietta's right to seek a second medical opinion and her ability to make informed decisions about her care. Henrietta suffered terribly in the short time between her diagnosis and her death. The initial vague discomfort in her abdomen soon morphed into excruciating pain. When doctors discovered a hard mass attached to her pelvic wall, almost blocking out her urethra, they collectively agreed that the cancer was fatal. However, all of them failed to inform Henrietta about this. They literally sent her home to die and only recommended radiation when her physical suffering became unbearable.
The radiation was meant to "shrink the tumors and ease her pain until her death," nothing more. However, neither Henrietta or her family members knew this. They believed that doctors were actively working to cure her; they didn't realize that Henrietta was actually dying. So, "benevolent deception" takes away the patient's right of personal agency and his/her ability to make informed choices. In that sense, the term is a paradox: it doesn't live up to its assumptions or expectations.