This only happens via Tor and oft-abused VPN providers. "Showing ID" has two benefits:

1. It helps mitigate a lot of unsophisticated spam attacks, taking off server load and annoyance off users.

2. It helps to some extent with mitigating criminal affairs because any potential criminal that falls in the gap between "doesn't realize IP addresses may leak location information" and "knows how to use compromised hosts as proxy" can be picked off by the authorities once they're noticed.

Anonymity is gone and it's not coming back. We have to adapt and we don't get a choice. At least there's some minor upsides to it.