You will not find online betting platforms that openly offer bets on Cockfighting, because it will then get global attention from anti-animal cruelty supporters. In most of the countries where they do it, they do not even allow people to record it, because of the negative attention that fights like this will attract.
The casinos will also not offer it, because they will risk losing gamblers that gamble on other Sports .... and they might be against animal cruelty, so it is a very controversial subject.
I completely agree with your input, casinos can never offer such games, and not even for the fact that they could face backlash from those against animal cruelty, but more of the fact that they could face a total ban from operations due to outrage from the general public.
Cockfighting should never be a game or be seen or taken as a means of gaining excitement in the first place, but then, human being are never just satisfied, we have a lot of games already, we have different types of sports, from football to handball, to baseball, to hockey, to volleyball, to table tennis, etc. , and fighting games like wresting, UFC and so on, and coming down to race, we have the car race, bike race, bicycle race, normal human race, horse race, dog race and so on, a lot of sporting activities to chose from, bet on and find excitement in, but then, like I said before, human being are never satisfied , what is there in cockfight that it even interest anyone?.
