Cockfighting wasn’t merely “technically not outlawed” in OK, LA and NM in the late 1990s and early 2000s, it was openly carried out in such states. See http://abcnews.go.com/WNT/story?id=131142 It was a traditional recreational activity in those states and other parts of the U.S., and only recently was it banned.
I’ve never gone to a cockfight, not would I go to one, but it is not correct to equate cockfighting with dogfighting, bear-baiting and the like, which are activities that have been shunned by polite society for over a century.
Of the group cockfighting is the least offensive. Bear baiting is still allowed in South Carolina under a grandfather clause and I find it to be the most inhumane of the entire group.
The purpose of a cockfight is to force two roosters to attack each other until ultimately one of them dies or is critically injured. I would certainly classify it as cruel brutality to animals and I think most Americans would agree.
Per Wikipedia, dogfighting wasn't completely banned in all 50 states until 1976, but that doesn't mean it was still considered socially acceptable and mainstream in parts of American during the 60s and 70s -- its probably even more taboo in America than cockfighting because dogs are intelligent companion animals. As MarMema noted, Bear baiting is still allowed in South Carolina under a grandfather clause, and its probably the most brutal of the three blood sports.
In any case, I'd certainly place cockfighting in a similar category as dogfights and bear-baiting -- as a relic of a barbaric era, or as you noted: "activities that have been shunned by polite society for over a century" Cockfighting was once popular in American during the colonial era (I believe George Washington used to bet on cockfighting), but it fell out of favor by the civil war era, and it was outlawed in most states decades ago (despite three states being the exception to the rule), and I can't imagine the "average" voter in Kentucky would find it socially acceptable to have a cockfight. I've heard of public cockfights in third world countries like Vietnam and Peru, but not in places like New Mexico (and keep in mind those are the same countries that find it socially acceptable to EAT dogs. Barack Obama's childhood being a clear example ;-) )