Just my opinion.
I think the whole "Tom wants to be appreciated" thing is a big deal. I think as he grew, he was no longer the 6th rounder, crying in the Brady 6. He knew he was the GOAT and wanted to be a partner in the process, while Bill made it clear that he was the QB and that's it. Tom evolved and Bill didn't change how he coached him as he did, which rubbed him, and likely, his whole family, the wrong way. So there's bitterness and Dad is looking for a little payback. You hurt my boy, so now we must destroy you.
Meanwhile, Bill looks at this as an out of division, non-conference game and one of the least important, record wise, on the schedule.