The video makes some points about safety issues, and the possibility of combustion products (including C0) getting into the boat thru the mounting plate or muffler (if used), but the exhaust hose looks very weak also.
My impression is that when the production is supervised by a good company that Chinese products can be of good quality. For example Nordhavn Yachts were made there for some time. (Taiwan, Thialand and Turkey now I believe--maybe some still in China). I have had some optical products and electronics from reliable firms which were good quality.
On the other hand, to compare Harbor Freight with a quality tool from Milwaukee there is a real difference. Most of the Harbor Freight tools, I have purchased and used were either mechanical, like a clamp, or for a one time use--such as a small diameter cutt off wheel. I picked up a Dremel knock Off--and it was crap--same with their bits etc.
If I were buying the heater, I would go with the genuine product. It's like boat anchors--there are some knock off of CQR, but they never held as well as the CQR. Would I trust my boat to Chinese chain? No.
About a year ago, I bought a copy of a German electrical switch off Amazon. The first time it had a 200 amp load (rated for 300 amps,( the "real deal" had often been loaded over 300 amps.). there was a spectacular failure with arcing, melting of the plastic and sparks....not a warm and fuzzy feeling on a boat!