At least they’re not the Steelers… 
The only thing I have to say is that this post amuses me greatly.
It may not seem it, but I really did not intend on this being a discussion on Spygate. The main reason for this is that I thought it was already a given that Belichick and the Patriots cheated in a significant way, and that their past victories are, and always will be, in question. In fact, any internet search on this matter and its details suggests that I’m right. CBS news, The New York Times, and other respectable news sources have all written about it.
However, dopers are usually smarter, more inquisitive and hopefully more open-minded than the general population. I’m also willing to be more open-minded about the Spygate issue, since so many of you have concluded that it was much ado about nothing.
Cite?
At least the wiki article doesn’t seem to indicate any major organizations thought it helped all that much.
Jimmy Johnson didn’t think it really helped that much and notes that it was a common practice back in the day.
Don Shula though, as you do, that it tarnished several wins. But he coached the division rival Dolphins. And he’s got a history of other douchey behavior.
Most players and coaches seem to think it a minor issue. Certainly, there wasn’t nearly this kind of backlash when the Denver Broncos were caught last season. But they had a losing record and don’t have nearly as much vitriol tossed their way on a daily basis by rabid fans.
Sports columnists may have said it was a moral outrage that compromised all of the team’s wins, but that doesn’t prove much of anything.