John F. Kennedy was an avid supporter of immigration. From the late 1800’s to the 1920’s the majority of the population was dedicated to immigrants coming to America in search of a better life. Many of these immigrants worked hard labor and dedicated many new ideas and inventions to the industry. Breakthrough technologies were introduced by immigrant backgrounds. Kennedy refused to let there be a second class in the caste system, he believed from the start that all men were equal no matter their origins. Immigrations greatly impacted the interpretation and attitudes of society, the work industry, and American History. Much of these reasons are the very ones that Kennedy recognized, and refused to let a democracy be the judge of taking away civil rights from those of a different country.
He accepted himself of how he looked.
This is something you should decide, it does not have an straight answer.
Your answer should be WHO.
Think of it like this: You wouldn't say "The boy it (a variant of 'which')", because it simply just sounds odd. Instead, you're wired to think "The boy, he (an unknown name, so it would be 'who')".