Here's Twitter's documentation on how they identify state-affiliated media[1].
This excerpt makes the decision seem outside of the defined process:
State-affiliated media is defined as outlets where the state exercises control
over editorial content through financial resources, direct or indirect
political pressures, and/or control over production and distribution. Accounts
belonging to state-affiliated media entities, their editors-in-chief, and/or
their prominent staff may be labeled.
State-financed media organizations with editorial independence, like the BBC
in the UK for example, are not defined as state-affiliated media for the
purposes of this policy.
