Now we know, and yes, it was intentional:
U.S. Analysts Knew Afghan Site Hit By Air Attack Was A Hospital
Not only did they know, they wilfully targeted it, because, purportedly, one of the secret ennemies in the secret wars the U.S. has been waging on the basis of what is called laughingly "intelligence", was assumed to be in the hospital.
Days before the Oct. 3 U.S. air attack on a hospital in Afghanistan, American special operations analysts were gathering intelligence on the facility — which they knew was a protected medical site — because they believed it was being used by a Pakistani operative to coordinate Taliban activity, The Associated Press has learned. [...] The special operations analysts had assembled a dossier that included maps with the hospital circled, along with indications that intelligence agencies were tracking the location of the Pakistani operative and activity reports based on overhead surveillance, according to a former intelligence official familiar with the material. The intelligence suggested the hospital was being used as a Taliban command and control center and may have housed heavy weapons.
Of course the whole "intelligence" thing is a crock. We know for a fact that there were no heavy weapons, no command and control center, because that's not the way Doctors without Borders operates. Maybe there was somebody in their building calling other people too much on the wrong cell phone, and even that is far from certain, since intelligence analysts are so notoriously error-prone, to borrow Charles Pierce's mantra.
Is it even worth mentioning at this point that, had the hospital been housing Bin Laden himself, such an air strike would still have been a war crime?
Throughout the 19th and 20th century, rules were developed. It was increasingly considered good form at the very least to pay lip service to civilization. Areas were designated safe havens. The Geneva Convention was signed. From the end of World War II on, bloodthirsty dimwits calling for carpet bombings, blind assassinations, and generally "taking the kid gloves off" were kept on a somewhat shorter leash, with the occasional lapse (Nixon, e.g.). All that has gone out of the window. The Barbarians are back in the saddle, and blowing to bits wedding parties, hospitals, and entire families on the basis of hearsay, which is essentially what "intelligence" is, has become the new normal.
Welcome to James Clapper's world.