If a meter is claimed to be good for a particular CAT rating, and you put the test voltage for that CAT rating through it, and it catches fire, it is shit. There is nothing wrong showing the word that it is shit. The big Chinese vendor could certainly have sued Gossem over the video if they think it is unfair.
The big issue with these crap meters is that they end up in the hands of laymen, because they are so cheap. I have seen the shit sold at supermarkets in the home-improvement section. Between wall paper and paint a selection of crap multimeters with a range going up to 250 Volt or even 600 V or 1.2 kV. The laymen looks at the range, if at all, and has no clue about CAT ratings, fake CAT ratings and fake safety marks.
Not to long ago I had an argument with a neighbor, who was proudly showing of his *shudder* analog *shudder* Protek HC5050E. Not even a CAT rating, but it had a CE mark. Well, or maybe an Chinese Export mark. The highest DC range was 1.2 kV, the highest AC range confusingly labeled P-P Up 840, and a separate socket even labeled P-P 3300 AC 1200V.
3.3 kVpp AC in that cheep plastic case, sure.
And the best of it were the probes. The probes had no rating, too. The wires were sold to the metal tips and the tips loosely screwed into cheap plastic housings with no strain relieve. Normal wear and tear and the wires will at some point come loose and you end up with a blank wire in your hand. Just hope you don't have the other end connected to something > 48 V.
Less than 30 € buys you this engineering wounder from Hung Chang Co. Ltd.