There are two sides to that argument. He wouldn't need to say it if he was confident he presented only facts.
I mean if we want to get technical, he says: Everything I share in this video reflects my personal opinions and experiences only. This is not a statement of fact about Kuwait Airways as a whole, but rather an individual perspective based on one trip.
So he's presenting the fact that he got threatened on this flight. He's making it clear he's not saying it's a fact that you're all going to get the same treatment whenever you fly with them which would open him to a lawsuit very easily.
Now we're just arguing small points in the video. I still stand by my original post of this was totally unnecessary escalation by the purser, especially after the passenger that complained was also chill with it when she saw the footage had nothing worth getting crazy over.