In one of the threads about the Zodiac cypher, which had been unbroken for 51 years despite being given to the NSA, FBI, and the crypto community at large, there were several people who remarked how simple it was and how easy it should have been to crack.
Dunning Kruger doesn’t cover the entirety of what’s happening, but there’s some pathology at work here.
Meanwhile, the Zodiac story also demonstrates you don’t need to be a nation state to craft something sophisticated. Obfuscation and de-obfuscation aren’t on a level playing field. (This comment isn’t specifically about this attack.)