It is not my general inclination to believe that the DOJ routinely manufactures simple statements of fact out of whole cloth. Others on HN do have that inclination, sometimes powerfully. Regardless: (1) this is an unusually straightforward criminal complaint; it is short, spare, and composed principally out of simple falsifiable assertions, and (2) we're just randos on message boards talking and have no obligation to continuously and tediously disclaim that the DOJ has the burden of proving its assertions at trial. We all know it does.
It would not just have to prove the facts, but also convince a court of its interpretation of the law, on which the DOJ does not have the final word. Of course, we also know this. In fact, none of us needs to bother to comment, because whatever the courts decide is the law, is the law, and nothing else matters.
Except of course that these are normative arguments; you clearly feel that, fundamentally, someone speaking at Pyongyang blockchain conference deserves to be prosecuted and possibly convicted, and you feel that this would be just regardless of what a court might ultimately decide on the matter (since you ultimately don't know the outcome).
Some people apparently feel that the guy should not be prosecuted or convicted based on the actions he has been accused of; if there is a law that says otherwise, then maybe the law is wrong.
Others might fear that what they feel can be an inhumanely cruel system will come down on a person in a way that will not serve justice. And who can blame them. Frankly, those people are the ones with a functioning moral compass.
The other side of the coin is, teaching North Korean leadership (an infamously brutal regime) about how to evade international sanctions via cryptocoin technology.
How many millions of people have they "come down on in a way that did not serve justice". Aiding such a brutally repressive regime should absolutely be a crime.
And yes, the world is not perfect, and many nations get away with similar sorts of crimes (although almost universally on a smaller scale), that doesn't make him some sort of good guy.