When you hit a national security target, you get NSA and CIA after you. They have vast resources to make your life difficult wherever you are.
NSA rather not to interfere, unless infrastructure is involved.
Interference from public sector may actually not be successful in the long run, as companies simply adjust to that, and keep ignoring security at a new equilibrium level.
But yes, ransomware does lead to a hardening of network infrastructure, and reduces the likelihood of successful espionage operations, by alerting parties - via the ransomware attack - to security vulnerabilities.
For the same reason that neither them, nor the Army doesn't serve drug warrants, or investigate tax evasion. Because policing is not their mandate. That's the job of either your local police department, or the FBI, or any one of a number of the other federal police forces.
You don't just get to sprinkle 'potential threat to national security' to turn criminal activity into a problem for the extra-judicial arms of your government. How about we let the police do their core competency - policing, and the military and the spooks to stick to their core competency - extra-judicial violence, and kidnapping random people to hold/torture without trial in Gitmo.
Your comment seems to imply you think the most/all of the remit of the CIA is or should be invalid. That position doesn't contradict my comment in any way.
That is a rather different claim than saying that premptively pursuing ransomware gangs in other countries is outside what the relevant decision makers view as the remit of the CIA. To me it seems to clearly fall in-line with their historic actions (as long as the cyber ransomers are outside of the country.)