Those incorrect statements are a byproduct of which lubricants you purchase and which system is commonly used for specific markets. The truth is that ISO and SAE are very much the same thing as saying a 12 mm bolt or a 1/2 inch bolt. Different measuring systems, nothing else. Still bolts. It helps a lot to have the charts ingrained in your mind, or a chart handy:SAE oils are for automotive use.
ISO oils are for industrial aplications.
Sometimes we can do a crossover, but it isn't ideal.