Confusing remark; I haven't sleuthed the standard in over a decade, but DDC/CI v1.1 (available for free here[1]) § 2.3 makes this abundantly clear:
>> The DDC/CI display is considered a fixed address display device at adddress 0x6Eh / 6Fh, and uses only I2C slave mode to communicate with the host.
...while § 3.3.1 specifies addresses for external display dependent devices.