There is a much simpler, less dramatic explanation.

Ear monitors come in sets of 2, guys. That's just how they are made and sold.

There are two ear pieces, which are connected to eachother by wire, and then to a small pack which is strapped to the performer (usually in a pouch somewhere on the back). The pack sends and receives wireless signals to and from a pre-amp. They're basically just like regular ear-bud headphones, only much better quality, and often fitted to an individual's ear. Cutting the unnecessary wire for the left ear monitor (1) is just plain stupid because they cost a fortune, and (2) might damage the monitor's function.