Data in a dat, just like data in a torrent, only lives as long as there are peers interested in seeding that particular dat; it's not a blockchain-style "everybody has to replicate everything".
You can't unilaterally withdraw content somebody else is also seeding; the best you can do to my knowledge is publish a new version that replaces all the dat's content with a "please delete your history of this archive" message, but as with any distributed system you have no real way of knowing if that was respected.
You can't unilaterally withdraw content somebody else is also seeding; the best you can do to my knowledge is publish a new version that replaces all the dat's content with a "please delete your history of this archive" message, but as with any distributed system you have no real way of knowing if that was respected.