" Fuck major labels! " came the mohawked cry from the Warped Tour mainstage as Rancid, the traveling punk circus’s de facto headliners, prepared to tear through their half-hour set last Thursday evening at Suffolk Downs. The swarming crowds of sweat-soaked kids — some 18,000 of them paid the $25 ticket for the six-stage, day-long event — roared back their approval. " Fuck the Yankees! " came the response from the stage. Again the crowd roared back its approval.

It may have been a cheap way to get the kids on their side — major-label suits are punk’s perennial enemy, and August in New England is prime Yankee-hating season. But with the temperature pushing 100 degrees, the humidity hovering somewhere in the 90 percent range, and worn-out teenagers starting to desert dusty Suffolk Downs in defeated clusters as early as 4 p.m., this clearly wasn’t the time or the place for subtle gestures. Besides, with those two statements, Rancid zeroed in on two crucial components of the Warped Tour: the old-school, anti-establishment, DIY punk values that define much of the music; and the alterna-jocks (skaters, BMX bikers, rock climbers, etc.) who, by doing their things in designated areas while bands like Rancid kicked out the classic jams, skew the event toward the X-treme-sports demographic.

Rancid’s anti-major-label sentiments, which have their roots in the grassroots hardcore scene that spread throughout the American underground in the early ’80s, may seem a little anachronistic in an age when it’s become hip in an ironic sort of way for even underground artists to cash in on the mainstream’s appetite for alternatives. And the Warped Tour, which is officially known by its corporately sponsored name the Vans Warped Tour, would have a hard time filling all six stages if it eliminated acts with major-label deals — the MCA-signed H2O would have been off the mainstage, and second- and third-stagers like Lefty (Interscope) and Alien Ant Farm (DreamWorks) would have also been out of a gig. (And let’s not forget that last year’s de facto headlining act were Green Day, one of Warner Bros. flagship alternative artists.)

Still, a big part of Warped’s appeal, both for the bands and for the fans, is nostalgia for the black-and-white, us-against-them glory days of American hardcore, for slamdancing on the frontlines of a cultural battle, for the days when punk had a real purpose. Nevermind that it was never all that simple, or that the very fact that the Warped Tour gets to take over Suffolk Downs for a day proves that punk no longer faces the opposition it once did from the powers that be. In fact, the real struggle for contemporary punk bands like Rancid is not to be co-opted by a mainstream that’s eager for access to the 18,000 consumers who bought Warped Tour tickets. On the other hand, there’s a certain strength in numbers, and a certain fleeting power in corralling thousands of sweaty kids to roar approvingly, whether it’s against major labels or a major-league baseball team.

And regardless of where you fall in the indie/major or Red Sox/Yankees argument, there’s a lot to like about the Warped Tour. For starters, there’s the reasonable ticket prices coupled with a full-roster of bands and the almost complete absence of downtime between mainstage acts: the two-sided mainstage means that while H2O were finishing up their set on the left, Rancid were setting up their gear on the right, and one set led right into the next. And though you could argue that by telling the major labels to fuck off Rancid were indirectly giving major-label H2O a hard time, in general the Warped Tour seems to generate a good vibe among its parrticipants. Indeed, bands are generally given the opportunity to play prime slots when the tour hits their home town: last year at Suffolk Downs Green Day ceded the top spot to the Bosstones, and this year both Rancid and the all-star California punk outfit Me First and the Gimme Gimmes went on before Boston’s own old-school punkers, Dropkick Murphys.

The Warped program is mostly punk, but the tour always offers something in the way of diversity — the reggae band Morgan Heritage got a mainstage slot this year. Ultimately, though, like OzzFest, Warped is more about fortifying the walls that separate us from them — i.e., punk from unpunk or metal from everything else — than about tearing them down. And for most of the day it was hard to see beyond Suffolk Downs.