Not the down voter, but if you look through guidance from the malpractice insurance industry (e.g., https://www.thedoctors.com/articles/medical-and-dental-recor...) you will see that defense against potential malpractice claims is a key driver of retention practices. Introducing a right to be forgotten in healthcare would presumably require concomitant reform of the medical malpractice landscape.

I'm not arguing against the sentiment (and indeed I think patients should have a much stronger ability to audit and control how their records are shared, including the ability to opt out of sharing) -- but when it comes to records retention by the originating organization, it's important to evaluate these practices in the broader context.