Most politicians might know nothing about Crypto currencies, but they have well informed advisors that are doing the ground work and research for them. A lot of the Banks also have financial advisors that are more than willing to give bad advise to these politicians and they are just one phone call or one secret meeting away.

There will never be a shortage of people who wants to score some brownie points with these politicians, so there are an abundance of resources out there for them to use.

The average politician probably has little or no understanding of cryptocurrencies. Some might understand the basic idea of a blockchain and its decentralized nature but the percentage of lawmakers who know the difference between a private key and a public key, the process of setting up cold storage wallets, or how multi-sig should be implemented securely is almost certainly very, very small.
So if cryptocurrency does become regulated and businesses like exchanges are forced to implement security practices such as having most of their funds in cold storage, then who will decide what regulations should be implemented and how? Surely, it won't be the politician.
as in everything else, they'll defer to experts/advisors/lobbyists.
I wonder what kind of qualifications would be needed to become a cryptocurrency advisor.
An advanced degree in computer science and/or cryptography could do it, but they would lack the financial knowledge. Someone having all three would be a hard find. The alternative would be to scout for those who regularly contribute code to cryptocurrency and blockchain projects, but a lot of the top minds in crypto are devs posting under anonymous/pseudonymous handles who don't give a damn about economics, finance, or anything that isn't about the code, and even if they do care about the wider perspective, chances are they will probably want the government to keep their hands off crypto anyway.