@verius @nerthos Grounding a non-insulated device to the chassis is actually very common in industrial applications, but that is because the case itself will be "bonded" (electrically connected) to the facility's grounding bar or other method of grounding, so it is harmless.

It is improper to ground to the chassis if the chassis is not bonded and this would not pass Canadian Standards Agency or British Standards approval, but the people there are describing a US unit.  It is entirely "normal" for improperly grounded devices to be sold in North America because the FTC standards about electrical safety are very lax.