History

At the time dog fighting was legal in England, it was also legal to beat your wife and children, to hunt and kill any beast for the sake of sport, and also legal to import the decapitated heads of Pacific Islander peoples (Pacific Island natives slaughtered solely for their heads, not as a result of disease or war) for decoration.

In an era when all game and humans from distant lands can be slaughtered to decorate some noble Englishman's country home, it's hardly surprising that dog fighting would be legal. However, even back then it was not considered a "gentleman's sport" but rather the blood sport of the wharfies and uneducated farmers of the British Isles. It was a substitute for the fox hunting and big game hunting the rich could afford to do.

If a society has not tendered itself to the cruelty of blood sports and the rich participate in them, of course those in a lower socio-economic group are going to imitate as best they can and that's what they did with dog fighting. It was also tolerated because it provided some financial income for those who had a low income or no other way to provide for themselves or their family.

Two years after importing human heads became illegal, dog fighting became illegal in England, and these changes in British law came about as a result of the first Reform Act of 1832, which William IV at first opposed. Later, towards the end of his reign, he changed his stance and adopted several liberal laws which included banning importing human heads and dog fighting. It was seen at the time as the reformation of a once well-traveled and worldy man and a pious outcry from that man repenting for a hard-lived life and the blood shed in England. When Victoria, his niece, came to the throne in 1838, these laws were further enforced and have remained to this day. It was also during this era of bloodshed that the importation of African peoples by the British began in the United States for the purpose of slavery.