It wasn't about the taping it was about camera placement. In fact the Jets could have legally taped the Patriots signals during the same game and probably did.
In the old Jet stadium the camera booths were located on the opposite side of the Patriots sideline so it would have been impossible for BB to have a camera located with the same filming advantage as the jets had during that game.
BB ignored a memo about camera placement on the sidelines which wasn't a "rule" and Spygate was born.
Taping the opposing team's sidelines still may be legal today. Not sure how helpful it would be trying to memorize hand signals though.
They like to say that deflategate was a makeup call for spygate but both should have been frivolous in house type issues but the Puppet and a few of his owners decided to take the Pats down a notch.
The popular national consensus is that the Patriots would never have won anything without the Tuck Rule, which they invented, advocated for and applied themselves surreptitiously.
And that their illegal videotaping is solely responsible for their ever winning anything.
And that the destruction of the team's logo and uniforms was a wise, appropriate, and justified action and that they had no identity, history, heritage or tradition; that the team is essentially second-class citizens, unworthy of having their historic look out on the field with their opponents, several of whom also have long or even longer histories with their logos and uniforms.
And that old Foxboro Stadium was crumbling far, far, worse than say, Cleveland's Municipal Stadium was when Modell moved.
And on and on...
And that the Patriots' on field record was worse than over a dozen other team's, which in fact are.
And that one day several African-American Patriots players suddenly morphed into perverts, making lewd gestures toward a woman pretending to be a reporter, later pretending to be a victim, who was miraculously able to identify specific assailants and their unconscionable acts, all while working and writing and reporting. After all, NOW, People magazine and Paul Tagliabie all said so, specifically that the Patriots "damaged the league", just like they did again in '07
And that the Patriots were involved in a huge drug scandal in 1986, while their opponents were all squeaky-clean.
And on and on...