I've often wondered the same. For some reason, I always want to know about 'Silvergun Superman.' I tend to think it's about cheating spouses.
Scott said that it's about a friend back home that betrayed him.
Hasn't Robert dated Scott's girlfriend? So, it's about him:
"Wait for me, take a dive, take a piece of my life
Wait for me, tell a lie try to take my wife"
hahaha