Angry fans say the Glazers have saddled the team with enormous debt, leaving storied United hard-pressed to sign top players and putting the club's future in doubt.
Team officials say United is doing just fine, and the Glazers, who also own the NFL's Tampa Bay Buccaneers, generally don't say anything. The protests have been harsh and personal, and the owners rarely attend games.
Efforts to reach spokespeople for United were unsuccessful Thursday. A spokesman for team's North American tour referred all questions to the team.
On Wednesday evening, in a parking lot outside Lincoln Financial Field before the game, Andrew Burton draped a huge black-and-white banner across his car. It said, "Love United, Hate Glazer."
"I'm fighting for my club," said Burton, a 47-year-old native of England who lives in Richmond, Va. "It's worth fighting for."
The lifelong United fan said he was nearly arrested after taking his banner into United's game last Friday in Toronto, the opening match of the five-city tour.
At the Linc he planned to play it safe by handing out green-and-gold balloons.
"We're not xenophobic. We're not anti-American. We just want them out," Burton said. "They are raping the club, and I'm here to protest. Green and gold until they're sold."
In another lot, wearing a green-and-gold T-shirt emblazoned "United 4 Life," 24-year-old Ben Wagner spoke in frustration.
"They're draining the club into poverty," said the Washington public-relations agent. "A team like Manchester United, you can't have owners who are just out for themselves."
American sports fans may be shocked - shocked - to hear that the wealthy owner of a sports team might seek to wring from it every last cent. And, of course, United is hardly impoverished. Forbes Magazine ranked the club as the most valuable in all sport, worth $1.87 billion.
But United fans say their situation is different.
For them, United is less a team than a religion. And Old Trafford is their church. With steep increases in ticket prices under the Glazers, some are finding it hard to make their way to the pews.
John Nolan, an England native who took time from his job in Saudi Arabia to follow the tour, said several friends had canceled their season tickets as prices doubled in recent years.
"You can't keep rolling that debt up," he said, a green-and-gold scarf around his neck. "It's not an 'American' thing. It's that they keep taking money out."
The Glazer family bought the club in a debt-leveraged buyout in 2005. David Gill, United's chief executive, denied to the Times of London that the debt - reported to be 716.5 million pounds, or nearly $1.1 billion - hampered the team.
United said in a statement that the Glazers would not sell or entertain offers for the club.
Nolan and other fans complain that the owners see United solely as a financial vehicle.
"I'm here," Nolan said, standing by an entrance gate. "I've been to Toronto, and I'm going to Houston and Kansas City. Are the Glazers here?"
United began the tour with training sessions in Chicago, followed by a win over Scottish power Celtic FC in Toronto. United travels to Kansas City, Mo., for a game Sunday against Major League Soccer's Kansas City Wizards and will be the opponent at the MLS all-star game in Houston on Wednesday.
The 44,213 watching at the Linc were largely United fans. When Gabriel Obertan scored the game's only goal in the 76th minute, the place erupted.
Fans made the stadium an ocean of red, punctuated by smaller seas of Union blue and flashes of green and gold. The protest colors reach to the club's 1878 formation as Newton Heath LYR, composed of workers from the Newton Heath Lancashire & Yorkshire Railway Co.
This year the world's most famous player, David Beckham, seemed to support the insurgency when he left the field wearing a green-and-gold scarf.
But Beckham, playing for A.C. Milan, said he had not intended to endorse the movement. A fan handed him the scarf, and he put it on, Beckham said, telling English newspapers that United's ownership dispute was "not my business."
Some fans in Philadelphia felt the same way.
Gerald Mazani, 28, a restaurant manager from Washington, was neutral on the green-and-gold movement.
"I'm not for it. I'm not against it," said the Zimbabwe native, who grew up watching United on TV. "I'm just about the team."
Contact staff writer Jeff Gammage at 215-854-2415 or firstname.lastname@example.org.