Mark Zuckerberg Claims Reported 5,000-Square-Foot Bunker Just 'A Little Shelter'

Mark Zuckerberg's not building a doomsday ranch out in Hawaii ... claiming reports of his 5k-square-foot basement have blown rumors about his Kauai home out of proportion. Waiting for your permission to load the Instagram Media. Here's the deal ... Bloomberg's "The Circuit" posted uncut footage from their recent episode, where Zuck attempts to clear the air on last year's WIRED report that he would have a…