You can’t have both ‘sockpuppet-grade anonymity’ and ‘held liable for their actions’ in the same society, whether Internet or otherwise. Both in reality and online, those that create sockpuppet corporations-slash-identities are unmasked only when their web of sockpuppetry is pierced by e.g. ‘reused a mailbox’, ‘used a neighbor’s identity’, ‘used a family member’s identity’, and so on. Until such investigations, sockpuppets get away with billions of dollars-slash-gigabits of crimes every year, and barring the ever-incompetence of most criminals, the Internet is a vast improvement over shell corporations in that regard. Still. It is technically possible to be able to ban the controlling human of an online sockpuppet without violating their anonymity, but we lack the societal infrastructure to do so — and since our own techno-utopian societies have invested no effort in doing so, it seems like the core utopian ideal could be ‘freedom from consequences’, rather than ‘freedom of anonymity’. If that’s a valid interpretation, then the core issue is not ‘preserve relative anonymity’, it is ‘preserve relative non-liability’, which may offer new avenues for much cheaper investment than pseudoanonymity would cost.