Well there's anonymity from authorities, and there's anonymity from garden variety lunatics.
There exists a grey area between not getting away with nefarious activities, and not having your life ruined by a lynch mob because you didn't approve their preferred CoC on a hobby project or some other perceived injustice.
Is there? The government apparatus that's meant to investigate these crimes is the same one elected by the mob.
If you find yourself a member of any group a campaign can mobilize the mob against, that entire investigatory apparatus can be turned against you.
Without privacy, we are doomed to endless purity purges.