TLDR: “privacy” services can’t be bothered and you shouldn’t too if you are not doing illegal stuff.

These “privacy-oriented” services are businesses that need to earn money, not scare away potential clients and avoid legal issues. Accepting cash or crypto is a risk for legal and accounting reasons. They just don’t think it’s worth it.

Now, to link a particular activity on a particular service with you via your payment is not a trivial task. Government can do it, but it really matters if you think you are or will be targeted by it. Data miners can correlate bank payment with an account at a service provider only if both bank and service provider sell or leak data, which is less likely if you are using a privacy a oriented service.