If you create parts for a bomb and hand them to someone else, knowing they are likely to use it as a bomb, and they in fact do, you are as guilty of conspiracy as the actual bomber.
Your crime was complete when you gave them the parts, which is an overt act (some act in furtherance of the conspiracy).
(Unlike the typical gun analogies that get brought up in response, i'm choosing something that does not have a legitimate purpose and is in fact illegal to create as-is)
If you create a thing in the US that is required to comply with KYC/AML and don't, and someone users it to launder, and you know they use it to launder, you are still guilty even if you couldn't stop them from using it.
Again, your crime is complete at the point you complete an overt act .
You have to withdraw from the conspiracy before then.
Here, the government is charging them for the website, mainly, not the smart contracts
See page 24
Not "they created a tool and it got misused" but instead "these specific criminally sanctioned folks are using our tool to launder 600 million dollars, and we know, should we do something about that?"
Their messages back up that they know it was being used in a specific instance, by criminals, to launder money, and they did nothing.
Sorry, no sympathy. I'm with you that we need to ensure tools are available, and i'm even okay arguing about KYC/etc.
But when you have specific, actual, knowledge that a criminal actor is using your tool to launder money, and you do nothing, sorry, that's just aiding and abetting.