Shula was an NFL guy who took over the expansion Dolphins after the merger was arranged (and annually beat the Patriots at the Orange Bowl forever).
Rozelle brokered the deal behind Davis' back, as it was clear that Al was never going to overlook or forgive the NFL for its actions and behavior in the sixties, particularly against the AFL (why would anyone with a conscience?). So, Rozelle was #1 on Davis' **** list from then on and he knew it, and cut the Raiders some slack because let's face it, he knew the NFL owners were scum too, he just did what he did to make the league profit, and he clearly succeeded.
Going along with the Raiders' indignation over feeling robbed by the immaculate reception (they weren't) was a way to appease them, and certainly directly led to the atrocity in '76. Anyone with eyes who saw it then is deluded if they do not agree that that Super Bowl should just be vacated. Raiders fans, like lots of fans, just see what they want to see. John Madden is a nice man, but tainted and illegitimate just begin to describe that season's result. Of course, Davis had no problem moving his team later, especially against resistance from the league.
An interesting coincidence, that the Raiders' title in '83 (with lots of ex-Patriots) was the last for the AFC forever, during which time the NFL owners were like pigs in ****, while (like always) neutral (or, real) football fans suffered.