This is a DNS hijack, not an HTTPS hijack. The ISP's resolver sees "casino.org" in the A/AAAA query, finds it in a blocklist, and responds with an IP address to a web server that serves a block page (or a CNAME thereto).
The HN link is to https:// ... a web browser cannot request the page, and cannot process a redirect unless the server responds with an acceptable certificate. If the server responds with an unacceptable certificate, the browser may ask the user to accept it, in which case the browser could connect and issue the request and receive the block or a redirect.
If the user doesn't click through the certificate error, the user will only know it's blocked (or the server is misconfigured), they won't get information on why it's blocked; perhaps details of the certificate might help narrow down the cause of the block or the agency implementing it.
If the user loads the https page and sees "Access to this page is disabled The law prohibits participation in games of chance organized by unauthorized persons through means of electronic communication." as suggested earlier in this thread, and the user did not click through a certificate error, then the MITM must have obtained an acceptable certificate somehow or broken TLS. Since Sep 2024, multi-perspective issuance corroboration has been required by the CA/Browser Forum [1] and it was a best practice for many years, DNS takeover in a single country should be not sufficient to establish domain control for certificate issuance.
