> I'd argue nuclear physics is far more complex than cryptography

We're not talking about "being able to do it" but "being able to understand what it can do". Nuclear weapons are a lot easier to grasp than cryptography in that sense: it is a thing that explodes. It is absolutely obvious to everybody that a bomb destroys whatever is in the vicinity.

> Let's not attribute blatant malice to stupidity. People in these positions [...]

It's not people in these positions: the vast majority of the population doesn't understand the limits of cryptography.

> have the resources and advisors to know exactly what the consequences will be.

Seems to me like you haven't been in contact with lobbies and expert advisors. Many times, politicians will have to ask experts from the industry. They would not contact an average engineer for advice, but rather the company itself. If there is money to be made, the CEO or some executive will give their advice. This advice is systematically beneficial for the company. It's not necessarily malice: a CEO has to believe in what they are doing, even if it is objectively bad for society.

It is very hard to find unbiased experts to help you forge policies.