Shaz's customers have to earn money to transact with him, and like most of us, that means they're doing things they'd rather not do, but others value what they're doing so highly, they're actually willing to pay them to do it (employment). With that said, the work they perform is contributing something valuable to the rest of society, valuable enough for them to part with their hard earned money voluntarily. Their transactions with Shaz, and consumption habits may not be appealing to outsiders, but as long as they're not taking people's money without their consent (crime) it's basically none of our business how they spend their money.
Kurt on the other hand teaches Keynesianism. Aside from the fact this terrible economic philosophy has slowed the rise of the middle class, in favor of funding a military industrial complex, endless wars, and non-stop inflation, what Kurt is doing most likely involves people's money being taken from them without their consent. While Kurt's students are most likely there themselves voluntarily, or at the demand of their guardians, in the majority of the possible scenarios the students do not pay for Kurt's services themselves.
In this hypothetical scenario, Kurt could be a public school teacher. If that's the case, the funding for his disservices (teaching lies) are taken from people involuntarily, through taxes (threat of force). Kurt's services sound like a "great idea" on the surface (until you take the class yourself), I mean who doesn't think people should be educated? In reality, outside of this abstract thought) his services are so invaluable, the majority of people supposedly "benefitting" from them (the students) would never actually pay for Kurt's services themselves, in a voluntary manner.
If Kurt is a University Professor, the majority of the funding is through government backed loans, and grants, which is basically the same scenario with more steps. This leads to the same problem that Shaz's customers bring if they commit crime, people are being parted with their hard earned funds involuntarily. The only difference is the person pointing the gun at them, robbing them, will probably never face justice for their crime, so they co do it openly.