Editor's Note: Ruben Navarrette Jr. is a nationally syndicated columnist and a member of the editorial board of the San Diego Union-Tribune. Read his column here. Ruben Navarrette says liberal attacks on Sarah Palin and Joe Wurzelbacher are unfair. SAN DIEGO, California (CNN) -- I thought liberals were supposed to be good-hearted, open-minded and non-judgmental. Tell that to the angry Left's favorite piñata, Sarah Palin. As far as liberals are concerned, Palin can do no right just as Barack Obama and Joe Biden can do no wrong. In fact, Biden is catching more passes than an NFL wide receiver. As Palin herself pointed out in a recent CNN interview, imagine if she had been the one to imply that electing Obama would invite calamity. Biden does it, and the media shrug. I also thought the Democratic Party was supposed to go to bat for the little guy, the everyday Joe the Plumber. Tell that to Joe Wurzelbacher, the Ohio resident who got his 15 minutes -- and 40 lashes -- because he dared question Obama about his tax plan. Obama insists that the plan would raise taxes only on those Americans earning more than $250,000 per year. It was then Obama made his clumsy "spread the wealth" comment. What was Joe thinking: that we live in a democracy where everyday Americans who pay the salaries of elected officials can dare question their policies? That just isn't done. To prove it, the elites who run the Democratic Party -- along with their surrogates in the media and organized labor -- went after the plumber. We now know that Samuel Joe Wurzelbacher owes back taxes, doesn't have a plumbing license (he told the Associated Press he doesn't need one because he works for someone else's company), and may not be registered to vote. Commenting on a CNN.com story, one condescending reader wrote that Joe the Plumber should pipe down and "get back in my bathroom and unclog the toilet." Even Biden and Obama got in a few licks. Biden quipped to Jay Leno that Democrats wanted to take care of "Joe-the-real-plumber-with-a-license," and Obama sarcastically asked supporters, "how many plumbers do you know making $250,000 a year?" The implication being that Joe the Plumber isn't who he pretends to be. What worries me is that the Democrats aren't what they pretend to be. Obama supporters like to talk about how the Democratic presidential nominee has lived the American Dream. So why is it to so hard for them to conceive of a situation where someone dreams of earning more money a few years from now than they earn today. Has Barack Obama consumed all the social mobility this country has to offer, so there isn't any left for the rest of us? Now, the Obama-Biden boosters have refocused their attention on their earlier irritant, Sarah Palin. The latest media template is that the vice presidential nominee is a drag on the GOP ticket. Pundits detect a backlash, not just among Democrats who love to hate Sarah Palin but also among women, independents and seniors. They cite polls showing Palin with an unfavorable rating of 50 percent. So what? We're in the post-Clinton, post-Bush era of polarization where any politician with a pulse -- Sorry, Joe Biden -- will be loved by half the country and hated by the other half. It's surreal. Before McCain put Palin on the ticket, he was getting 200 people at campaign rallies, and now, when he appears when Palin, he gets 20,000. Yes, definitely a drag. iReport.com: Rock star welcome for Palin in Ohio McCain oversold it when he said Palin was the most qualified vice presidential candidate in recent history. Better than Dick Cheney? Could she be worse? Obama might have paid Biden the same compliment if his running mate hadn't already told supporters that Hillary Clinton would have been a better choice. Then there is the faux-scandal that the Republican National Committee shelled out $150,000 in the past several weeks on Palin and her family for campaign wardrobe, accessories, makeup, etc. Many Americans don't see why it's a story. Fellow hockey mom Page Growney of New Canaan, Conn., asked The Associated Press, "What did you want to see her in, a turtleneck from L.L. Bean?" Still, we're told, this tempest in a Gucci bag has some Republicans worrying that shopping sprees at Neiman Marcus and Saks Fifth Avenue might undermine Palin's everywoman image. To think, just last month, the criticism was that Sarah the Moose Hunter wasn't sufficiently sophisticated or glamorous. Now her wardrobe signals the hockey mom is high-maintenance. Just how many more caricatures -- some of them contradictory -- can we expect the left to throw at Sarah Palin before time runs out on this election? The opinions expressed in this commentary are solely those of Ruben Navarrette Jr.