As opposed to American hackers hacking American companies? Nationality has nothing to do with it, other than with jingoistic profiteers and/or morons who want a vaguely defined distant target to blame.
That's outside the scope of NSA's mandate. The NSA should not be using their resources to target American hackers or companies.
We should deal with such hackers too, using agencies like the FBI. I guess the NSA could provide some technical advice, but no more than that.
No evidence on American hackers should be classified or secret, unless they target government or military(and even then, the only thing that should be supressed from the public court record is the actual classified records that they stole, or details about the vulnerability they used). However, evidence the NSA gathers on foreigners and techniques they use could be classified.
The President should not intervene with diplomats if an American hacker hacks an American company.
I think these make the two situations very different in practice.