Medicare and Medicaid rates are not set by congress or legislature!   Medicaid State Plan Determines State Payment Methodology for Medicaid Services.  Under fee-for-service arrangements, states pay providers directly for services. States may develop their payment rates based on:

    The costs of providing the service
    A review of what commercial payers pay in the private market
    A percentage of what Medicare pays for equivalent services

Under managed care arrangements, states contract with organizations to deliver care through networks and pay providers. Approximately 70% of Medicaid enrollees are served through managed care delivery systems, where providers are paid on a monthly capitation payment rate. 

 The methodologies for service rates are described in the Medicaid state plan.

Educate yourself before blaming a political party!  Both medicaid and medicare were in place long before now, so have you been complaining your whole life or just now?