Also interesting is the language they used in the email they sent me after I requested account/data deletion:

We received your request to permanently delete your 23andMe account and Personal Information. The following apply when you submit your deletion request:

• If you chose to consent to 23andMe Research by agreeing to an applicable 23andMe Research consent document, any Research involving your Genetic Information or Self-Reported Information that has already been performed or published prior to our receipt of your request will not be reversed, undone, or withdrawn.
• Any samples for which you gave consent to be stored (biobanked) will be discarded.
• 23andMe and the contracted genotyping laboratory will retain your Genetic Information, date of birth, and sex as required for compliance with legal obligations, pursuant to the federal Clinical Laboratory Improvement Amendments of 1988 and California laboratory regulations.
• 23andMe will retain limited information related to your deletion request, such as your email address and Account Deletion Request Identifier, as necessary to fulfill your request, for the establishment, exercise or defense of legal claims, and as otherwise permitted or required by applicable law.

The first bullet point makes sense - you agreed and they already published something, so too bad. The second bullet is doing the right thing. But those third and fourth bullets sound like they don’t really have to delete anything, and they’ll keep a bunch of data even if you ask them to trash it. I asked them to trash it anyway.