The reason why journalists use that style of headline is that they know the story is probably bullshit, and don't actually have the sources and facts to back it up, but still want to run it.
A headline with a question mark at the end means, in the vast majority of cases, that the story is tendentious or over-sold.
To a busy journalist hunting for real information a question mark means 'don't bother reading this bit'.
[15] Phrasing headlines as questions is a tactic employed by newspapers that do not "have the facts required to buttress the nut graph".
[16][3] Roger Simon characterized the practice as justifying "virtually anything, no matter how unlikely", giving "Hillary to Replace Biden on Ticket?"
[17][18] Many question headlines were used, for example, in reporting of Bharatiya Janata Party in-fighting in 2004, because no politicians went on record to confirm or deny facts, such as "Is Venkaiah Naidu on his way out?
"[19] Because this implication is known to readers, guides giving advice to newspaper editors state that so-called "question heads" should be used sparingly.
[24] The Supreme Court of Oklahoma held in 1913, in its decision in Spencer v. Minnick, that "A man cannot libel another by the publication of language the meaning and damaging effect of which is clear to all men, and where the identity of the person meant cannot be doubted, and then escape liability through the use of a question mark.
[26] The New York World also famously used a question headline for hedging when editors were unsure of their facts, when it reported the outcome of the 1916 United States presidential election.
"[29] This was the result of a last-minute intervention by then World journalist Herbert Bayard Swope, who, having received a tip from gambling friends that Charles Evans Hughes might not in fact win, persuaded Charles M. Lincoln, the managing editor of the paper, to reset the headline in between editions, inserting a question mark.