It's not "setting the tone" it says that explicitly and even goes into detail into the implementation of how that is going to be enforced

> Implementation. (a) Within 120 days of the date of this order, the Director of the Office of Management and Budget (OMB), in consultation with the Administrator for Federal Procurement Policy, the Administrator of General Services, and the Director of the Office of Science and Technology Policy, shall issue guidance to agencies to implement section 3 of this order.

They even say they will review existing contracts

> (ii) to the extent practicable and consistent with contract terms, revise existing contracts for LLMs to include the terms specified in subsection (b)(i) of this section; and

> (iii) within 90 days of the OMB guidance issued under subsection (a) of this section, adopt procedures to ensure that LLMs procured by the agency comply with the Unbiased AI Principles.