If they really do blame this on the users
It's not that they said:
It's your fault your data leaked
What they said was (paraphrasing):
A list of compromised emails/passwords from another site leaked, and people found some of those worked on 23andme. If a DNA relative that you volunteered to share information with was one of those people, then the info you volunteered to share was compromised to a 3rd party.
Which, honestly?
Completely valid. The only way to stop this would be for 23andme to monitor these "hack lists" and notify any email that also has an account on their website.
Side note:
Any tech company can provide info if asked by the police. The good ones require a warrant first, but as data owners they can provide it without a warrant.