One issue in terms of data that I struggle with on researching this issue is that we're discussing a big empty space and wondering why it is empty. Immigrants in the US aren't allowed to build companies and create jobs unless they are very lucky/connected or they wait a long period of time to get their green card, since no visa currently exists for founders.
We can't do A/B testing to see if our suspicions that we'd have more startups and more jobs for US citizens if we allowed more founders—not more blanket immigration, mind you—into the country. The people who do find a way in tend to be the best and the brightest of the pool, so our anecdata looks favorable. There seem to be indications that immigrants and first-generation citizens tend to be 'hungrier' than more established populations, though that doesn't say anything about success/failure rates.
From a physics perspective, it's like hunting dark matter. We suspect that job growth would result from passing Startup Visa or STEM Green Cards, but economics theories are nowhere close to the rigor of physics theories. VCs still only invest in solid, market-driven ideas. I'd rather trust to them and to the market as a whole as to who sees success than have the government throw up artificial barriers to block non-Americans from American networks of capital and talent, especially when it means the failure to launch of startups that might make my life better.
Kauffman does indicate that young companies produce the most net job growth in America: http://www.kauffman.org/newsroom/kauffman-foundation-analysi... , though as Steve Blank says, 'startups' are lumped together when there's a large differentiation that needs to be taken into account: http://steveblank.com/2011/09/01/why-governments-don%E2%80%9...
The best bit of public policy analysis I've seen on Startup Visa and implications for job growth is from the National Foundation for American Policy (NFAP), but they studied the 2010 Startup Visa, which is much more limited than even the 2011 Startup Visa. The 2011 version of the bill doesn't address STEM Green Cards and is strictly limited in an attempt to pass a conservative House of Representatives, whose majority has a strong anti-immigration faction.
So we're left with all of the arguments that you state. However, note that a thoughtful person like yourself isn't the target audience of something on CNN. The NFAP analysis is probably more 'chewy' for someone who wants to dive into the issue.
EDIT: Forgot the NFAP link: http://www.nfap.com/pdf/092910NFAPPolicyBriefImmigrantEntrep...