>From Khrushchev's own words (27 October 1962):

That dosen't refute anything from his own words as a justification as opposed to his primary goal to provide Cuba with defence here to deter a US invasion. As others have pointed out, the USSR was annoyed by these placements in Italy and Turkey earlier, but they did not declare war or start a crisis over it beforehand. It's more that Turkey was a bargaining chip here.

>>Our aim has been and is to help Cuba, and no one can dispute the humanity of our motives, which are oriented toward enabling Cuba to live peacefully and develop in the way its people desire.

You need to place here in context that the Jupiter missiles in Turkey were already obselete but the US had the overwhelming advantage in a nuclear strike with their Atlas ICBMs in USA at the time, relying more on a fleet of intercontinental bombers that could targeted by NORAD.

Removing nukes for Turkey did little to change the strategic calculus, but it did heavily deprive the USSR of an opportunity to change that calculus with Cuban nukes at the time, which was a major factor in Kruschev's later removal from power.