IIRC, the overlapping games flowed out of a situation a few years ago when one game was postponed to Monday night because of a hurricane or something and they aired them both. Both games had great endings, so when the first one ended you flipped over to the last few minutes of the other and got another rush of instant excitement.
People loved it because both games were fun and were over at a reasonable hour instead of a late kickoff ending well after midnight EST. So the NFL decided to try it again and give people something they enjoyed. But because people are never happy, now they hate it.