IH founder here. Why do you think the title is exaggerated? He did start his business less than one year ago.
Of course, any business depends on the skillset and knowledge that its founders started to build previous to its founding, but how do you put a start date on that? To build a company, you need business skills, a network, money, programming knowledge... for that you probably need professional experience... for that you need the ability to read and write... etc. Where do you draw the line? Everything always depends on what came before it. People get this. They aren't naive enough to believe that founders are born on day 1 of their companies with no previous life experience or knowledge of the world.
I agree it's dishonest to refer to a 5-year-old business as "an overnight success" as often happens, but how exactly is it misleading to call a 1-year old-business a 1-year-old business?