Let's get one thing clear: Nobody pays zero tax in this country.
It's true: 47% of (adult) Americans don't pay federal income tax. This includes retirees (duh), the unemployed (obviously), and soldiers in combat zones (parasites, say the GOP). But it also includes a lot of working people and families, who get paid so little that the slightest additional tax is too much a burden to bear.
But they're not off the hook, no. These people still pay social security tax, medicare tax, state income tax, city tax, county tax, property tax, estate tax, sales tax, phone tax, cable tax, car tax, registration fees, inspection fees, license fees, work license fees, school fees, tolls, and all those other government charges us for the necessary things in life, as well as all those optional things: extra birth certificates, marriage licenses, hunting and fishing permits, cigarette and liquor taxes, and so on and so forth.
So when some jackass bitches to you that "half this country doesn't chip in", you can tell 'em to stick it where the sun don't shine and join us back in the real world any time they want to. Especially if he's running for president.