I always thought the book was Manifest Destiny but its not. The story that sticks in my head was a human in a cage over a pit? Aliens walk in and discuss how dangerous humans were. He eventually escapes. Man I miss this book. wish I wouldve written down every book I ever read. Ugh
Danger-Human! by Gordon R. Dickson has some elements of your question. A caged human is studied by an alien race that fears him. Fears him so much they surround his cage with a deadly acid moat.
Previous outbreaks of human conquest across the galaxy made it a taboo to interact with humans. The human escapes at the end and the aliens are afraid they just restarted another era of human conquest.
The 1973 publication is correct as well.
You can read the full text online here