The belief that corporations should serve anything other than the interests of their shareholders, particularly with respect to the interests of the workers or abstract intellectual principles is something you hear from libertarians all the time. That the employees of Cato themselves thought they were anything other than agents engaged in labor in service to their shareholders does come across as pretty hypocritical.
I know a lot of libertarians, and not one of them has ever suggested that employees of a company should not try to get the best deal for themselves if at odds with their employer over pay/working conditions/whatever.
Libertarianism has a fairly strict social hierarchy which makes the role of an employee quite clear. It’s hypocritical for the Cato employees to think that they were somehow exempt from this relationship. The Koch brothers told them what they expect them to do and how to behave. That they think there should be some other arrangement speaks to a hypocritical belief that these Cato employees are somehow “special” in a way that most other employees are not.
“Corporations are people, my friends.” The libertarian ideal is one in which the Cato Institute has no abstract purpose for its existence other than maximizing the value for its shareholders. Cato’s employees are insisting that instead it should, unlike their belief about every other corporate institution, be leveraged to benefit themselves and some abstract ideological service to “libertarianism.”