Anonymity leads to the multiple accounts issue. Pseudonymity addresses that. Eg: "We don't know the name of the person behind this identifier in real life, but we see we blocked them last year, so we will deny their request to open a new account with us"

You and I agree the moderation here on HN is fantastic. There is a minority of people who would prefer HN allow spam, bigotry, calls to violence, revenge porn, snuff content, etc. A large community - a nation, for example - should have the ability to 'tyrannize' an antisocial minority into enforcing some base level of standards. For example, at a minimum, to prevent a site operator from showing those types of content to users who do not specifically request them.