This is just them being lazy or trying to set a baseline of TPM 2.0 based systems. There's no technical reason to not support those chipsets already supported in Win11.
What features did they add that required newer chipsets? It made sense sense for windows vista because of all the 3d/glass effects. For windows 11 all they add was... rounded corners.
Macos 12 runs on Ivy Bridge 2013 mac pro's and haswell mac minis, so on their side it wouldn't appear to be a technical limitation of the older CPU's. Apple does their trusted stuff on the T2 rather than the Windows generic TPM 2.0 requirement, but interestingly the 2013 mac pro lacks a T2 as well. I think TPM 2.0 was a 6th gen skylake onwards thing?