Choosing U.S. products over foreign ones isn't protectionism. It's a personal decision to support America and Americans, instead of China and Chinese.
I've always been suspicious of "Buy American" and believe it hurts us in the long run because it breaks the basic rules of economics (capitalism). If American products are inferior, yet people keep buying them, then the businesses have no incentive to improve. Meanwhile, foreigners will be forced to make better products to convince the "Buy Americans" to buy their products.
Our products will be more inferior, theirs more superior, and our industry will lose in the end because you can only hold off the laws of economics for so long. And it's not only internal, because other countries will buy other foreign products when ours suck, thus our exports go down.
Of course, if you want to "Buy American" you can always go with IBM, Red Hat, Novell, Cisco, TiVO, Linspire, Oracle, MontaVista, Terra Soft Solutions, etc., all American companies.