I interpreted it more as (like the title implies) Jack’s inherent racism. Due to the type of company he usually surrounds himself with, the only time he ever hears the term “Puerto Rican” is in a negative context, in which someone is using the term as a way to insult someone or complain or something. Jack does not have a diverse enough friend circle to actually have ever heard someone use the term “Puerto Rican” to refer to someone’s ethnicity without making some sort of judgement on the person.