GDPR covers EU residents so you don't need to be a citizen (i.e. you could travel to EU and delete all your data) - see chapter 1 "your company is established outside the EU but offers goods or services to, or monitors the behaviour of, individuals within the EU."

EDIT: reading a bit more seems that some companies think that its only when a data subject has data processed within the EU (i.e. they data subject is in the EU) or the data processing is done in the EU.