Why does apple restrict my apple cash after I verified my identity with my ID and after calling apple support they just tell me that it’s still restricted and to call back in 30 days?

Probably because your identity or other accounts of yours are compromised. They don’t know if you’re you or the fraudster.

Another possible reason is past transactions may be under investigation. Banks report suspicious activity to FinCEN (Financial Crimes Enforcement Network). FinCEN has about 30 days to complete an investigation.

https://applecash.greendot.com/termsconditions/

Apple has nothing to do with this really. Banks operate under federal and state charters and can’t be influenced by outside parties. Federal and state regulators watch what banks do to be sure all the regulations are followed.

Why is positive ID required?

The Patriot Act requires that lenders, banks etc obtain a confirmed ID.

“To help the government fight the funding of terrorism and money laundering activities, Federal law requires all financial institutions to obtain, verify, and record information that identifies each person who opens an account. What this means for you: When you open an account, we will ask for your name, address, date of birth, and other information that will allow us to identify you. We may also ask to see your driver's license or other identifying documents.”

See, If your Apple Cash account is restricted or locked - Apple Support