I remembered 0W-20 for other countries but not 5W-30. Didn't know that video was discussed previously.
It did make sense as anything that is suppose to perform variable fluid pressure has to take into account the liquid viscosity. A water pressure washer will not make the advertised PSI pumping a 5W-30 motor oil; and will definitely fail prematurely.
Anyhow, I don't think the guy is necessarily clueless. Maybe it's a general (reasonable) advice for the majority of people who don't research and perform UOA.
Good to know about 5W-30. Thanks!