Say what you want about those cheating on their spouses, but their sexual preferences, fantasies, and credit card information should be kept safe.
Sure, these people are cheating on their spouses, but a lot of time the people who do this are ones who feel so uncomfortable with their current spouse that they can't even open up about their sexuality. They feel trapped and helpless knowing that they can't even open up to the one they love, and most of these people feel incredibly stuck either financially or because of family things. There are people out there that are so terrified of their kinks coming to light, because they love their partner, but they also know their partner would not be accepting of whatever kink they might have.
Can you imagine someone having, say, a foot fetish. They love their spouse dearly and love their children, but the spouse would be disgusted with even knowing this person has said fetish, and if they divorced and the foot fetish came to light the family courts would definitely make it extremely hard for this person to gain any sort of favourable custody (It's so extremely common for people in the kink scene to lose their children in custody disputes that there's a reason many don't "Come out,").
This is horrible and disgusting and I really hope these people are caught before any person is blackmailed like this. These hackers are threatening to out these people to their bosses, for Christ's sake! I really hope that when they get caught the courts don't go easy on them, either.