Your position is classical historical revisionism.
Prior to Goodell issuing the memorandum which explicitely prohibited sideline filming, it was common knowledge that this was a means of gathering competitive intelligence that was practiced by multiple teams. One of the points made during this period was, I believe by Bill Parcells, that such information gathering is why a majority of teams changed their play calling signals on a regular basis and it was therefore shocking that certain stubborn teams would not change their signals, thus creating a potential competitive advantage that the Patriots and other teams would gleefully exploit (hence the commissioner's memorandum, which was sent to 32 teams not to 1 team).
Why do you think there was famous footage of Herm Edwards looking directly into the Patriots camera? The answer is because it was common knowledge that this was happening.
Steve Marriuci tells the story of Lions staff picking through the garbage of visiting coaching staff looking for playbook and playcalling information.
It is ridiculous on its face to single out the Patriots as one evil entity contrasted by 31 other teams with pristine records of never attempting to obtain competitive advantage.
Belichick's real error here in incorrectly reading the tea leaves and failing to anticipate that the league had made up its mind that enforcement of the new guidance would be swift and harsh.
There are basically two reasons why Belichick has been vilified, those being unprecedented success and presenting a non-sympathetic character. People don't like the man because he sent a married woman shoe boxes full of cash and he quit the Jets job when it became apparent that he was being installed as a puppet. Unfortunately, some people are just fundamentally dishonest, and rather than saying "you know what, I just don't like the guy" they say "he's a cheater and the only reason they've ever done anything is because of cheating and they get an asterisk and blah blah blah". It's horse hockey.
Cue the response of "we'll never know because the league destroyed the tapes". Whatever dude. We know what we know, Belichick got made an example of, and the tempest in a teapot becomes the foundation for fragile rhetoric from whiners who don't like the man. So much so that thinly veiled counter-attacks from jealous owners ("deflategate", "spygate 2.0") become added to the "foundation" of the "cheater" label. It's pitiful. To be the man, you have to beat the man.