Pointing to a guy who’s been dead 50 years seems like weak evidence for the claim that government agencies are widely incentivized to undermine political candidates by… selectively leaking their grocery shopping habits?
They’ll look for anything they can find, when they need to. There are whole organizations devoted to digging up dirt, and others devoted to countering/deflecting it.
Risk minimization sounds prudent if you’re a target.
If the very first director of the FBI immediately abused his position to blackmail everyone around, what do you think has been going on in the intervening 75 years?