Black Hat is one of the largest hacker conferences in the world. The others being DefCon and CCC.
They tend to be anarchist/libertarian types who want full control over their tech, and see no problem hacking their shit even if companies say it's not allowed.
Now that does extend into illicit activity for sure, hacking for fun and profit is a very common phrase. So I'm not trying to downplay the black hatters, but it has a hacking connotation not a satanist one (although there is for sure overlap there).
White hat hackers hack into systems and inform the target of vulnerabilities whereas black hat hackers will steal your shit with the thought being you're too stupid to secure your shit so it's free. Gray Hats are hybrids who will break the law, but tend to not steal your shit.
So yeah, it's a very old conference, with the best hackers in the world. Do you want to know that hackers can remotely take control of your car and kill you if they want to? Then don't worry so much about the name and just focus on the content.
By the way, one of the favorite games they play here is "spot the fed". So there's definitely an understanding of what's going on on all sides. It's not hidden. It's in Vegas for obvious reasons.