Wasn't it JFK who negotiated down the Cuban missile crisis? I would have thought both Cuba and Russia would be more than appreciative of JFK, why would they assassinate him?
Its the US that has since shown us, over and over its appetite for assassinations all over the planet, and war, not Russia and definitely not Cuba, so I am not sure your logic there.
History has shown us it's the peacemakers who are assisinated, to make war, not the warmongers - the warmongers are who do the assassinations dude.