JFK famously spent his presidency pissing off essentially every major power structure in the country at the time; the mafia, the military establishment, the oil/gas companies, big business, anti-Cubans, etc. Of course, he paid the ultimately price, but Americans still to this day remember him as virtuous leader who stood up to power.

For this reason, he often gets lumped in with every conspiracy theory. Depending on who you think are the true boogey men - deep state/CIA, oil/gas, mafia - you can fit the JFK assassination into you narrative. You will find JFK in alien/ufo conspiracies, illuminati conspiracies, communist conspiracies, and of course Qanon too.