Datasheets are written by different engineers from different countries, not everybody is thinking on the same way, sometimes they make mistakes too when they write the datasheet (in many cases not the designers write the datasheets).
I don't think CMRR should be the same next to any condition, definitely it depends on the circuit/feedback network around it. Datasheets should contain the worst case open-loop CMRR I think, but it is not bad if there are more information, like what happens with different closed loop gain values, with 5% tolerance devices, etc.