The block has been implemented using a hosts based method. Such methods work in HTTP as anyone on the network can intercept the traffic and modify it. This snooping is not possible in HTTPS, hence the word secure.
(Update: The above statement is misleading. Please read TallGuyShort's comment for clarity).
This kind of block sometimes take time to propagate given how our ISP networks are setup. The blockage can be implemented at any level. ISP, acquiring ISP, backbone etc.
But even HTTPS can get blocked via DNS provided you are using a DNS which is under the influence of DoT. Most internet users use Google DNS(8.8.8.8) or OpenDNS(208.67.222.222) or Berkeley DNS (4.2.2.2) as their DNS (They have fallback ips also). This is set in your network adapter settings or router settings. They are not under the influence of the DoT. I am not sure if there is a DNS block as I use Google DNS.
Also, IP based blockage is possible which restricts access to HTTPS sites but it is not the case here.
Censorship is no solution to piracy or terrorism. Burying your head in the sand doesn't solve the problem.
Edit: Updated to read TallGuyShort's comment.