Only because of LBJ. By today's standards, Kennedy was a moderate Republican.
JFK created "today's standards", without the stolen 1960 election we would live in a modernized version of 1950s America, not in a doomed America waiting to see what kind of unAmerica, multiculturalism will eventually melt into.
Imagine America without the 1960s, Vietnam, Lyndon Johnson, Senator Ted Kennedy, the 1965 passage of JFK's immigration act, press 1 for english, Muslims, etc, etc, etc.
Imagine an America with the unchanged demographics of 1960.