I'm a young Cowboys fan who is 30
Sorry, I meant to add the explanation for my above post not just a movie trailer.
The movie is of course North Dallas Forty, which is a fictionalized story of the Cowboys, masquerading in the book/film as the North Dallas Bulls. It primarily is following the escapades of WR Pete Gent and his friend QB Don Meredith.
And this is the core of why there's been a hatred of the Cowboys.
See, when the Cowboys were founded in the 60's they were just another football team. The team had Bob Lilly, Mr. Cowboy and not much else early. They had a fantastic hard nosed, very conservative straight down the line coach in Tom Landry.
Enter Tex Schramm the Cowboys GM and Gil Brandt the chief scout. Schramm decided to redefine the Cowboys and reinvent the NFL. He'd been GM since the beginning but he wanted to add to the Cowboys something more, something greater, especially with the rising popularity of more aggressive AFL style football.
He marketed the Cowboys as "America's Team" and took lead on initiatives like adding cheerleaders, moving the goalposts to the back of the endzone, and encouraging the merger with the AFL.
He also did not hate the image of the Cowboys in the decadent 70's. He embraced the glitz glamor and showmanship. He didn't shy away from the harsh hard drinking hard drug image of guys like Gent and Meredith. But he also embraced guys like Staubach and Lilly who were seen as paragons of virtue.
During Schramm's days there were all kinds of wild parties at his house, wild stories of the Cowboys getting up to no good. Lots of glitz, lots of glamor. I know I was there as a child, my father worked for the team, I learned the smell of weed at 3 by the Cowboys coming over to my parents house to play on our Atari VCS. A certain film about a girl named Debbie was out in that era.
The Cowboys were hated by a lot of people then and it stuck, their swagger, their arrogance, their 70's style Studio 54 Image was hard to shake, even with guys like Landry and Staubach who were literally pure as the wind driven snow and didn't even get slightly involved.
The disdain stuck into the 90's and got worse after, and of course we had Irvin and some others that continued the "North Dallas Forty" image.
So the Cowboys are a lightning rod, they love the spotlight, always have. It's Schramm's legacy and as much as people hate Jerry for it, Schramm started the tradition. People that don't love the Cowboys hate them, even if they don't know why. It's not new, it's history. I wouldn't have it any other way.