I've just looked at CNN and there's a piece from an hour ago there's no confirmation.
I'm not sure why the baby beheading became a big deal - we are sure they killed and burned babies, children, women and even dogs. At point blank.
We are pretty sure they raped (there are quite a few evidence by now).
We know for sure they beheaded adults (I saw pictures of beheaded soldiers).
Oh they also make it a point to murder hostages and send their loved ones a video of the murder. Great bunch of people.
If they did or didn't behead a baby doesn't really matter much imo. If they didn't does that somehow make everything alright? They did plenty.
It's easy to have the bias that this must be ruse to justify war. But it's just as easy to have the preconceived notion that the conflict must based on false premises, even though this is not inevitable.
I'd say you're wrong to dismiss something like this completely, given the confirmed videos that have emerged so far
It is a horror show.