It is a cynical and paranoid viewpoint admittedly but not all that irrational when it is in the playbook of spies willing to commit very dirty tricks. Their secrecy and known misconduct creates a void where speculation becomes disturbingly "reasonable". Note rational and right are two different things - Stalin's father was convinced near the end of his life that his son was evil and going to murder countless people - he was right in the end.
Even if not true it is rational to consider in the same way asking "Why would a mob boss choose to have an enemy killed?" is kind of a dumb question - the question is why not at this point.
Granted it is important to keep the speculations well ordered as there are crucial differences between levels like "proven to have done it", "proven to have done somthing like this before", and "are responsible for everything bad in the world".
Venezuela is a good example for a baseline. The regieme has proven themselves complete incompetents that have had to replace sections of civilian industry with untrained military and the CIA has toppled many South American governments. Thus while it is technically possible the CIA sabotage created a power outage maladministration is a more likely culprit especially since blaming foreign powers for internal problems to hold power is a time "honored" tradition.
For a counterfactual if the outage was followed by an invasion it would be hard to believe the CIA didn't cause if their plan was just "wait until it collapses for a peacekeeping causus beli".