Maybe we should have just referred to plain "Barack Obama" over here because fuck this President shit, we don't have an elected head of state in the United Kingdom?
and the story was broken in the Financial Times,
a British newspaper.
Best I can tell, Sir is a title bestowed by the monarchy on people they like.
https://en.wikipedia.org/wiki/Honours_Committee
(Do you think the Queen was enthusiastic about knighting Elton John or Mick Jagger? https://www.cheatsheet.com/entertainment/the-real-reason-que...)
Also, not all jobs come with an associated title. I'm a software engineer, but people don't refer to me as Software Engineer Joe Bloggs. "President" absolutely is used as a title. This is especially clear with former presidents, who retain the title. (E.g. George Bush, who isn't president, is still President Bush.)
> all living former U.S. Presidents continue to be addressed as "Mr. President"
President isn't Obama's job any more. Sadly.