The most probable cause was the fact that back then, no one really cared about who was nominated for VP. Most of the attention was given to the presidential candidates. So, it's likely that Mass. liked Eisenhower, and voted for him both times.
Also, Kennedy was from Massachusetts, if I'm correct.
Yes, of course. But Massachusetts never supported presidential-candidate Nixon, against Kennedy
or anyone else.
(They even supported McGovern in 1972 over Nixon, and I've always ridiculed them for it. They were the only Democratic state back then, and that's why they were also the only state not to ever support him for president.)