Shopping precincts are often privately-owned public spaces, and sometimes one's rights there are unclear. In enclosed malls, though, like the one in this video, it's perhaps best to stop filming when asked. On the other hand, it's definitely best not to threaten and assault someone who refuses to do so, and this angry mall cop might have some explaining to do to the real ones.
While it's true the shopper is unmasked (or removes his mask during the confrontation) that's clearly not what the mall cop is mad about.
BONUS: we're in Scotland.
Ah just knock it out yer hand a wee bit, aye?
UPDATE: It's the Kingsgate shopping center in Dunfermline. They're taking the shopper's compaint "very seriously".
"We acknowledge the actions by members of our security team falls below the high standards of professionalism expected by us and our customers…" wrote Neil Mackie, manager of the shopping center, in a statement. "The act of producing video or still images, is prohibited under Home Office guidance in privately owned places open to the general public and this is clearly stated at every entrance to the Kingsgate Shopping Centre. However, it appears we failed to communicate this in an appropriate manner to Mr Newton."
"Would it be funny if I fuckin knocked you out, aye?"