Securing ipV6 is orders of magnitude harder than securing ipv4.
I have yet to read a book that shows the author understands it well enough to explain it.
Since the "experts" cannot explain it right, then how are "new" experts supposed to be able to secure it.
I have reasonably secured many a network with ipv4. As soon as ipv6 was added, suddenly all the machines that had ipv6 enabled were exposed directly to the internet, despite being behind firewalls with rules to block access. They were directly reachable via their ipv6 address. Since the default behaviour on ipv6 is to make something globally accessible, I can see why government organizations would be slow to adopt it. They already have a hard enough time securing their networks with ipv4, why make it easier for the dark side to access your "secured" content.
I have followed many "lock down" howtos for ipv6, and none of them worked.
I'm not claiming to be an ipv6 expert, just have enough experience with it to realize there are real hurdles to adoption, that many people seem to want to gloss over.