The remark is that the two words, while apparently interchangeable, in actual use are not. One is often used with positive meaning related to dexterity and so on. Also, they have different political meanings. So they are not at all symmetric in actual use, much like every other word pair
and many languages related to these. Some Slavic languages have a close cognate between words meaning 'right (direction)' and words meaning 'right (correct)', although I didn't immediately find examples in current use on Wiktionary where the two forms are identical. A "dated" example is Polish
I don't know if these linguistic phenomena definitely occur in non-European languages, but I think that many people in the Middle East, many parts of Africa, and South Asia consider the left hand unlucky or impure not only because it's weaker in most people but also because it's conventionally used when going to the toilet. It would be a little surprising to me if that attitude didn't show up in languages from those places too.
