It is so common for inserts to be unbalanced. I have a British console at one place where the Insert Return load is the master fader, top and bottom. They spared every expense on that baby!
My perfect equipment world would have all inputs mandatory balanced, and outputs whatever. Aahh the bliss. . .
But as said before, if you don't hear anything dont sweat it. The exceptions are lesser than the norm.
My short list of "hissy-fit" equipment are the Culture Vulture and the Retro Sta-Level. For the price of the Vulture, they couldn't design it with balanced I/O? And the Retro just wants to listen to the radio sometimes- different studios, balanced or unbalanced equipment situations.
Mike