And I WANT TO SEE THAT!
There's zero reason I can see that the RI can't be selected by the user. It simply provides options and new data points.
The reason is clear. The purpose of printing to match a colorchecker proof is to match the proof. Absolute Colorimetric Intent IS what ones uses to match colors. Using any other Intent will not produce a match and intentionally so. This would just confuse people trying to make their own profiles. The patch luminosity will be reduced and the colors shifted to the paper white point. Your desire for additional "data points," is nonsensical.
Of course, if your goal is to force a 'better' match to make the product 'appear better' the current behavior makes a lot of sense from a marketing perspective.
It seems X-Rite's goal is obvious. To make it as easy as possible for people to see if their profile generation workflow and spectral measurements were w/o some significant error.
I'm curious who told you that the RI in this module is Absolute Colorimetric.
Who told you 2+2=4? This is not rocket science and I'm frankly shocked it isn't obvious to you that I1P prints the proof image in Absolute Colorimetric Intent.
But that aside if you want to "SEE THAT" do this simple experiment:
1. Grab a profile from a paper with high OBs with the spectral data embedded. Plop it into I1P.
2. Create a new profile from that data.
3. Print the CC proof image. This is required since I1P doesn't let you print a proof image unless you just created a profile.
4. Now put the CC proof template over it, in normal (minimal uV) light you will see the printed gray patches have a nice yellow tint. Now look at it outside with the template and they will look neutral.
This is because daylight has close to the uV light of D50 and the profile was made with M1 illuminant which is based on the same. Absolute Colorimetric Intent adjusts the colors by adding a bit of yellow so that when viewed in daylight the fluorescence shifts that yellow back to a neutral color.
All other Rendering Intents do not and the CC proof would appear bluish not neutral in the same light.