1. It seems to me that inviting government examination and regulation of network traffic, in the name of security, seems unlikely to make the 'net _more_ flexible, and potentially could lead real rigidity that would be bad for development of 'net businesses and degrading the experience possible over the 'nets.
2. Stuff like CISPA is generally validating of 'net control regimes such as in Iran and China. As the malice of those becomes ever more apparent, US policies viewed as precedents and justifications will be suspect, as will supporters of those policies. Supporting this stuff will be like supporting tobacco companies and netting dolphins to catch tuna -- and may cause deep customer suspicion in a field where trust will be crucial.
Now item item 1, more rigidity, could be seen as positive for incumbents like FB. To which I'd would say that technology has already evolved around a lot of rigidity and that any business founded on a particular regulatory environment is dated to the moment when technology obviates those regulations.
Item 2 is more speculative, but I actually think more likely to prove telling. But it's going to take 5 - 10 years.
Someone more knowledable of CISPA could do better. The broader point of my remark is, figure out how those details relate to the Facebook business model and speak to that. Do that and you'll have an audience. And there's no need to rush, the stock will be around for a while.