I don't think this is entirely a leftist thing. Judaism is institutionally preoccupied with viewing every question from all possible viewpoints, which sometimes leads to them looking for the dark lining in the silver cloud.
That's why the final act in a Jewish wedding is the newly-minted husband stamping on a wine glass. To remind them that even on this most joyful of days they must remain aware that life is not without suffering. Or as Psalms 2:11 says, "Rejoice with trembling."
Thank you for that explanation. It is often overlooked when dealing with the Jewish people.