You're focused entirely too much on the crypto aspect of this. He conspired to aid a country in invading sanctions of the United States. He asked the US State Department for permission before going, meaning he knew there could be potential legal consequences ahead of time. The State Department denied his request. He went anyway, provided information that the United States could prove he knew could be used to evade sanctions, and then returned to the United States after committing the crime.

The crime has very little to do with the actual content of the presentation or the information he provided, or crypto whatsoever.

How it is a thoughtcrime if he literally traveled to North Korea to help them?

It's not required that this help is useful. Plenty of spies transferred information that was already known by the recipient country, fake information, or even information that was deliberately passed to them by counterintelligence - it's still espionage.

> almost a thoughtcrime

We’re free to discuss how Pyongyang can evade sanctions. In public, right here. We’re not free to travel to North Korea and say “here you go.”

It’s not a subtle difference.