What William did was not menacing. The paparazzi was stalking and taking photos of his children. Any decent parent would have reacted in a defensive manner when it comes to protecting their children from such violation of their privacy. And William’s reaction was fairly restrained even when he was angry.
As for pointing his finger at MM, that doesn't make him violent and abusive either. He was defending his wife, and also we don’t even know whether what Harry wrote was true because some of the stuff that was written in the memoir contradicted the truth.
Pointing a finger at someone or the anger that was shown in the video is nowhere even close to what Harry did. He literally pushed a photographer that caused him to cut his lip on his camera, and he also slapped his bodyguard and a musician on their faces. What harry did was violent, and definitely not mild or restrained. And I would say slapping their staff on the face is abusive behaviour. The fact that he, along with Meghan, have faced bullying complaints is also cause for concern.
there’s been reports of William having a temper and yet the one video proof of his temper shows his reaction to be fairly restrained and nowhere near violent and over the top like harry’s.