Black hat or white hat, I bet we can find a way to kill the Tarrasque with it!
Seriously though, CO is a tool, and like all tools, isn't inherently good or bad. (Unlike Undead which are all evil, if you go by 3.5
)
The (various) CO community generally is in the White Hat camp. Who do you think finds all the broken material? If they were Black Hats, the first time you'd see it is when it walks all over your campaign, like a giant, radioactive, fire-breathing CoDzilla. Its the CO folks who find the issues and push for errata, making the game better in the long run.
Generally the accusation that CO is "the debil" comes from RP fanatics. Oddballs that think that taking Skill Focus (Profession) is the height of RPing, and taking Power Attack is a sin. People who can't grasp that if you want a character to be good at a profession, that ranks easily represent that without the cost of a feat. I've seen as much in game issues caused by the RP fanatics as I have CO work. The thing is, the CO is easier to deal with generally. You can make weak characters better to make the gap less and minimize the impact, or generally talk the player to tone down his problamatic combination. When RPers cause problems, they get defensive in my experience claiming they're "just RPing their character," or can't understand that they're hogging the spotlight making it difficult for the other players to do
anything. (A feat that only truly over the top characters can do via optimization.) I wouldn't call RP evil, or even call the RP focused community Black Hats (though their hats aren't as bright as the CO folks in my book).
Optimization is not good or bad, it simply is. Omnipresent and omnipotent.
