Cock fighting is a kind of gamble that bet is placed on the two cocks whereby if cock A wins all cock A supporters wins. It is a legalize gamble in some part of Asia
You're right this type of game is what has been evoke since the early days in gambling when there have not been any digital technology with gambling during that era, not only cock but gamblers also make use of other animals like rams to gamble in those days, this were best enjoyed on an open field with a numbers of spectators to witness the fight and also cast their bet, cock fight is as interesting and same way entertaining and gamblers still practice this type of gamblings till present days all over the world but common in the remote regions under rural settings.
That's understandable that cock fighting is an ancient game that was popular in a time when there was no internet and no such digital technology but the problem is why this sport is still popular in the current era in some areas?
There should be a complete ban on this sport and there should be extreme punishment for those who get caught playing this sport. When there will be no cock fighting, there will be no betting on it.
Unfortunately, that's only the reason why it's hard to completely ban cock fighting since it has already become a norm or a culture since it has been played for a long time. Also, there are some provincial areas in these Asian countries which have limited access to technology and the internet, and cock fighting is very commonly played in those areas. Other reasons also included are that cocks, or chickens are normally being killed for human consumption unlike other animals like dogs which are kept as a pet and not for food.
Still, I understand that this should be stopped and banned completely as these animals feel pain and should undergo these circumstances before getting killed.