I've seen a theory or two on why the Giants did what they did, in terms of measuring the footballs, informing the league and the media, but not making a formal complaint. There's a school of thought that the Giants were trying to subtly aid the Patriots by doing this. I have a different theory: Mara and Rooney thought it would be funny to rub Kraft's nose in it by treating this whole incident like a joke.
We all remember Kraft's bravado when he arrived in Arizona for SB49 and demanded an apology. We also remember how he turtled at the owner's meeting in May and accepted the penalties. He did that, in large part, because Mara told him he had no support. Mara is then conspicuous in his support of Goodell and Brady's suspension. Fast forward to this year, Mara and Rooney's team play each other. The Giants test 2 of the Steelers footballs and find them below the minimum level. These were the same circumstances under which Kraft's team and best player were screwed over. Instead of igniting the same kind of firestorm, the NFL shrugs it shoulders. Without even conducting any type of investigation, they declare that the footballs being below the minimum PSI isn't an issue. Then Mara comes out and says it's "much ado about nothing" and Rooney promptly agrees with him.
When Kraft's team was involved, it was literally a federal case. Mara and Rooney are saying to Kraft "These rules that we told you were so important, that we dragged you, your franchise, and best player through the mud over, they don't apply to us. We made you pay us $1 million, but when we do it, it doesn't affect us or our teams at all." Once again, Kraft was told to go home and get his shinebox. He and Jonathan just sit there silently and take it. Again.
