Because the government insures those accounts for hundreds of thousands of dollars each. If you want to benefit from the insurance then you can only use the account for purposes allowed by the insurance contract which excludes "high risk" activities which is defined to include essentially all sex related services.

I thought the government insures those for when the bank burns down. How does my employment come into play here?

Aren't bank accounts required to be insured? Is there any legal way to offer a "high-risk" bank account?