This seems a bogus assertion to me. I can imagine many diagnostic health test results that would be more sensitive to leak than DNA (e.g., STD and drug tests).
DNA sequencing is eventually going to be so cheap and ubiquitous that it will happen to everyone anyway.
Having published my own results (https://enki.org/2017/10/17/publishing-my-genome/), I really don’t buy into the idea that DNA is the most personal data that can be leaked.
(Nevertheless, there should be more obvious warnings to customers about how their data will be monetized.)
Edit: I think I failed to make clear that while I agree that DNA is "personal" data, I don't think it is the most "sensitive" personal data. If I had an identical twin and he released his DNA, I would not care. If I had syphilis and my test results were leaked, I would be upset about that.