I'm glad you asked.What is it with people losing their minds over mouthguard colours?
Mouthguards protect the teeth. The issues people are having point to a deep subconscious anxiety. In dream analysis the loss of teeth indicates feelings of helplessness and lack of control over one's circumstances. They can even represent fear of death. Obviously the people obsessing over mouthguards are expressing these emotions based on the circumstances of their football club, rather than personal circumstances. They reveal a deep anxiety about the current state of the club, the lack of influence or control over instigating necessary change, perhaps even an existential fear for the future of the club.
Or they've just had a gutfull of everything and will vent over any trivial thing that gets up their noses.