It's probably exponentially more complicated than most people think. I'm not going to defend government institutions because they always lean on excessive secrecy, the Mi6 are far worse. Hell I think their motto was at one time "secrecy always" or forever, something like that lol.
In fairness though, as I have considered this situation in a more sober manner having consumed a great amount of historical intelligence cases and tactics (being the victim of the low-level Creepy Ones here in Canada as well since I was a kid), there might be family members of sources which the CIA leveraged in the 60s for which the Russians or Cubans could trace back today. Maybe even some of them still alive if they were double agents in their 20s. 61 Years ago if a young, more easily recruited Russian KGB offer was 26 years old, he could still very well be with us at 87. Traitor George Blake lived to be 98, these double agents live long!
There is also the other consideration which might force Americans to face an uncomfortable reality. You can be sure the spy business is the dirtiest of businesses when not dangerous, what would Americans say if they found out that it was the Russians or Cubans behind JFKs assassination? Would that improve relations? Increase or decrease the odds of WWIII?
What if it were the fear many have and it WAS a rogue CIA cell? After all, the French Foreign Legion tried to kill their leader Charles De Gaulle. There have been rumblings, perhaps overstated that JFK wanted to reign in the CIA. Some say it had to do with poor advise for the Bay of Pigs fiasco ironically. I don't think this would have warranted an assassination, but there could have been a hardcore sub-group. Remember, this was the height of the Cold War and the CIA were engaging a nasty enemy. They employed similarly nasty tactics. It's better that than nuclear holocaust, right?
Obviously I don't have access to these files to know whether it is a risk to release them or not. If there is a poor reflection on the CIA, that isn't grounds to keep it secret. Over 60 years have passed, no one is going to blame them for poor operations even so many years later.
It's a tricky situation though if Americans remain in the dark. It's like most situations in the world in which sometimes secrecy allows the conspiracies to run amok and people wonder, "what are they hiding"? The conspiracies are often worse than the actual event, though the real story could be worse than the conspiracies sadly. In most circumstances I would hope there is a operational and/or legitimate national security reason why they are still secret.
My guess is that Oswald was radicalized by the Cubans or Russians, perhaps even as revenge for the Bay of Pigs or other attempts to whack Castro. There may be many sources that point to this but enough plausible deniability for the Cubans or Russians to distance the government from any proof of wrongdoing while still pointing to some citizen turning Oswald into a rabid hater of America.
There are many Russians in the KGB who have retired and commented on this in interviews. Most say, perhaps self-servingly of course, that the Russians didn't have anything to do with it. I've heard it more than once by different former KGB. I'm no spy, but one guy wasn't very convincing to me in him suggesting Russia wasn't behind it. A micro-sample, but if I saw that interview it means trained professionals in the CIA and other spy agencies saw it too.
Pompeo seems competent. I would hope he is able to objectively balance the various stakeholder interests before making such a recommendation. Trump isn't as radical on these issues as people might think, he will listen to the arguments of smart people in the know of which Pompeo was one.
en.wikipedia.org
