Yeah - that’s not what that video shows.
You piqued my interest because that’s not how it works on Royal engagements so I searched Twitter for it and found it there and on Reddit.
First, William is very clearly not angry, he and Kate are walking and talking to someone at Borough Market and you see William spot the press pool of photographers ahead, he quickly (and calmly and politely) asks his Comms person to get the press pack to move back a bit so that they are not blocking the way and getting in the way of the public access.
Having been in press pools like that covering Royal engagements you do get herded around a little but it’s needed because there are so many different reporters and photographers jostling for the prime spot to get the best access.
He wasn’t trying to get rid of them he was getting them to back up and create some space for the engagement they were trying to do - the comms person should really have been on top of that though before William needed to intervene.
Also it was interesting that using ‘Prince William angry’ as the search term brought up loads of manipulated videos claiming how awful and angry William is all the time. Including one which was of him having an animated chat about football to a member of the public but had been sped up to make it look like he was being really angry.
There’s definitely a social media campaign to try to smear William at the moment.