Years ago there was a case where someone built a business out of making hidden compartments in cars. He did an amazing job of making James Bond style hidden compartments that perfectly blended into the interior. He was later arrested because drug dealers used his hidden compartment business to help their drug trade.
There was an uproar about the fact that he wasn’t doing the drug crimes himself. He was only making hidden compartments which could be used for anything. How was he supposed to know that the hidden compartments were being used for illegal activities rather than keeping people’s valuables safe during a break-in?
Yet when the details of the case came out, IIRC, it was clear that he was leaning into the illegal trades and marketing his services to those people. He lost his plausible deniability after even a cursory look at how he was operating.
I don’t know what, if any, parts of that case apply to Pavel Durov. I do like to share it as an example of how intent matters and how one can become complicit in other crimes by operating in a manner where one of your selling points is that you’ll help anyone out even when their intent is to break the law. It’s also why smart corporate criminals will shut down and walk away when it becomes too obvious that they’re losing plausible deniability in a criminal enterprise.