If Belichick threw his paper notebook^1, would you assume it's because of the notebook? Or because his team just threw an interception, missed a field goal, or lost the game? I don't think we have any context as to what happened in that gif.
He threw the tablet because it wasn't working for him, per Belichick:
> As you probably noticed, I’m done with the tablets. I’ve given them as much time as I can give them. They’re just too undependable for me. I’m going to stick with pictures as several of our other coaches do as well because there just isn’t enough consistency in the performance of the tablets, so I just can’t take it anymore.
I see no called-out connection between anything in the article and the gif at the top of it. It's a good gif to go along with the article, but I don't think we can say "he threw the tablet in this image because he was angry with it".
Edit: this comment is at -2 at the moment. If I'm wrong, please make the connection. I earlier pointed out that coaches are often emotional^1, and we have no idea if him throwing the tablet is related to him being angry at it, or even if it's a recent image.
Consider a video of an office worker smashing their keyboard in frustration and an interview about the server being constantly down. If the article and comments section focused on the clear inferiority of Logitech peripherals you would probably wonder if brand prejudice was playing a role.
[1] For example: http://www.reactiongifs.com/wp-content/uploads/2013/03/Fuck....