with just an undergrad in econ and an MBA, but the problem you may have is that the large majority of economists are "free trade shills" (which by the way signals you probably aren't too keen on constructive input about why, but I'll give it a shot). Sure you can get economists - even highly respected ones - who are still fans of protectionism, but then you can get climatologists who don;t believe in human caused global warming and biologists who support creationism too. The majority don't, and the same applies here.
What people forget about economics, especially macro, is that it is by definition an impersonal study of aggregates and averages. By that I mean it takes little account of the standard of living of, say, relatively highly paid North Carolina textile workers when deciding whether free trade in textiles is beneficial. Instead it looks at the cost in real terms of textiles for consumers as a whole, and the efficient allocation of resources in the textile trade. So if we can all buy cheaper shirts in real terms, and shirts are being produced with the lowest investment of resources, then that little section of our standard of living and that little microcosm of trade has benefited, regardless of how many $15 an hour jobs in NC are replaced by $15 a week jobs in Bangladesh.
This article probably explains it better than I could, but this is one area where experts (I'm not really one, but I know enough to see why) are going to agree to piss you off quite consistently.
In short, the reason it's normal for syndicated econ correspondents to support free trade is because most economists do. It's not like they had to hunt for the "shills" in some back room plot - in fact they would be much more likely to have to do that to find respected experts who are NOT "free trade shills". Ironically, the old joke about economists and consensus has its exception the very subject that you think is so artificially created.
Now remember what you may think free trade is, or entails, or why it happened, is not what the majority of economists think. Where you may see a deliberate attempt to break up labor, economists see efficient allocation of resources. Where you may see exploitation of LCC populations, economists see a way to move from subsistence living to productive employment. Where you may see a race to the bottom for corporate profits, economists see an increase in standard of living overall. Where you may see an attack on the US working class, economists see relative advantage and the benefit of low cost imports.
http://www.stlouisfed.org/news/speeches/2004/06_15_04.html