This is HBO likely not being familiar with obscure British legislation as some others have pointed out they had to use dogs instead of actual
SCTOUS footage as there is a US law that forbids footage of the Supreme Court from being used.
The fact that you even consider this censorship only proves you likely never experienced what true censorship means.
There’s no law enforcing this except those which give the judges full control over their proceedings. They could let CNN in tomorrow if they so decided.