I don't like 'it is what it is' at all but mostly I find its useage (mostly by young, spotty men in cheap suits, estate agents or otherwise) laughable.
It has recent military origins, which is why it's been adopted more by men. It means 'some absolutely horrible, gruesome thing has happened, probably killing or maiming my colleagues, possibly as a result of a mistake, or accident, almost certainly serving no useful purpose. But, it is what it is' i.e. there is no point seeking to attribute blame, or even to understand, there is no reason. It just is and we must move forwards, quickly and calmly, from here.
That's quite profound really and very much the sentiment conveyed, about war as a whole, in Kurt Vonnegut's 'Slaughterhouse 5'.
So, when I hear some pallid youth, who'd be stumped if asked to do his on ironing, say, in earnest tones, 'it is what it is', about his best friend not being able to meet up for a 'cheeky pint' until 8.15, I think 'you silly twit, stop trying to attach an aura of gravitas to the mundane details of your comfortable life by seeking an association with a coping mechanism adopted by people functioning at the edge of humanity'.