They aren't. How about this...google them and read about them. Maybe you'll learn something new and get some accurate information.
They are huge and very protective which naturally makes them dogs that people would think of for fighting. ( I know its sad)
They are not fighting dogs historically, but working and now protection dogs. Any dog can be trained to fight, even little ones. Look up rottie groups for the history of the breed on www.akc.org/. If your thesis statement suggests that rotties are bred for fighting, that is only illegally and you will not find much research to back up your claim. ^_^
