My pet theory is that it's to throw a bone to OEMs. They came out saying "oop, 7th-gen and older Intel chips won't work, guess you'll just need to buy a new PC!" until someone over there noticed that their still-for-sale (at the time the requirements went live), few-thousand-dollar PC (the Surface Studio 2) was a 7th-gen chip so they made eventually an exception just for that one. Because "reasons".