Yes, I agree: that is what conspiracy theorists do regardless of the facts on the ground. But that's tangential to my point. People on HN found the "goto fail" bug damning because of the specific form it took (among other reasons), and I'm happy to point out how damning that form turns out not to be.
The fact that GnuTLS is extraordinarily unlikely to host an NSA backdoor helps my point, which is why I brought it up.
However, I would agree with a hypothetical conspiracy theorist who would disagree with your assumption: Linux may be the platform for many high-value targets and companies, so it's not quantity, but..."quality" of a sort.
Conspiracy theorists would postulate that the iPhone is a much more enticing target for the NSA.