They were originally made for controlling bulls - that's why "bull" is in the name (and bulls are real !@#$$@$!@#$). Just like their bulldog ancestors. Apparently unscrupulous people took that to the extreme and turned them all into bull-fighters - not dogs, bulls (again, real #!$#$%@#$!$). Dog-on-dog came later.
Thank you for your factual answer. Regardless of where one stands on an issue such as this, he/she should never withhold ALL of the facts and only dish out those which bolsters their opinions.