Dr. Vandertramp had once been unsure of the life of evil he felt called to. He was young, then, and concerned with ethical living, albeit in a very pragmatic way. The epiphany that had led to him accepting his true nature and his deeply-felt purpose as a human being had been this: there will always be someone who will do evil. If they're defeated, another will rise to take their place. So why shouldn't it be Dr. Vandertramp in that position, knowing that he could fight off all usurpers and do evil right?