I heard a radio ad the other day that had me confused right until the end. Two construction workers were speaking in a definite South Philly kind of way — you know: hard-working, average guys. They were making a list of what their co-workers wanted from the convenience store, including lots of fountain sodas and iced-teas — several per person. (All I could think of was that I'd never want these guys working on my house; they’d never get any work done because they’d be in the bathroom the entire time!)

It wasn’t until the end of the ad when one of the workers said, “I’ll pay this time. You can pay next time,” that I caught on. It was about the soft drink tax in Philadelphia, which just became law, making Philadelphia the first major city in the U.S. to pass a soda tax.

But this stupid commercial did make me laugh, and it helps me make my point, too. These construction workers are buying several soft drinks a day from a convenience store — where the prices for those drinks are higher than the grocery store — and they’re worried about a couple more cents per beverage? If a couple of cents was important to them, they should be buying their beverages in bulk from a big box store. The ad was a ridiculous argument against the tax, which is a 1.5-cent-per-ounce tax on sodas and other sugary drinks, including teas, sports drinks and energy drinks.

Slate pointed me to a television ad that's similarly ridiculous:

I have lots of thoughts about the video, but the real problem with both the video and the radio commercial is that they try to make people feel like they won’t be able to afford these all-important, I-have-an-absolute-right-to-them, sugary soft drinks. But if money is that big of an issue, maybe you should stop buying soda and juice with too much sugar in it. (The tax does not apply to drinks that are more than 50 percent of either fruit juice, vegetable juice or milk.)

The affordability of these drinks is not what should have people concerned.

The real problem I see with the soda tax — aka sin tax, sugar tax — is not that it’s going to make these beverages unaffordable for regular people or even people on a tight budget. I don’t believe soda taxes will put a dent in most people’s sugary beverage consumption or help the obesity problem in our country. The real problem is that soda taxes are arbitrary, and they open the door for other things to be taxed under the guise of health to raise money when the coffers are low.

Sure, you can argue that cigarette taxes opened the door to this issue, but cigarettes aren’t food. (I know soda doesn’t resemble food either, but that’s the category it falls in.) The problem is, where will it stop? Will a potato chip tax be next? How about a chocolate chip tax? What about a peanut butter tax? Peanut butter is very high in fat. That can’t be good, right?

To me, this tax is a money-making scheme shrouded in a cloak of concern for our health, particularly our children’s health. It’s not how we should be addressing our nation’s obesity problems or its money problems.

Editor's note: This story was originally published in 2010 and has been updated with more recent information.

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.