National Geographic recently published an article about, and video clip of, a moose losing an antler. This is normal and natural, of course, but judging by the comments of those filming the video, they didn’t know that.
I hadn’t expected it to happen that quickly and easily; and certainly the moose doesn’t seem to be particularly discomfited by it.
He probably started grumping about being lopsided.
Judging from the way he shook his head, it was probably itchy right before it came off. Likely felt relief just after the antler shook free. Maybe even felt like "I wish this other one would fall off, too!"
And small woodland creatures eat the fallen antlers. An important source of minerals in their diets.