Whether or not he had "Balls of Steel" is open for debate. He wasn't exactly very courteous, though. His wife and daughter were not aware of his plans and he left an awful mess in the kitchen. Couldn't he have done it in the driveway where most of the mess could be hosed down onto the street and into the storm drain?
Thompson lived to shock people and died to shock people. In short, an angry, bitter and sick human being.
The “Balls of steel” is in relation to the fact that Thompson did not whine and cry about “dignity”, he did the deed himself.