This article touches upon a very important part of human nature that becomes increasingly counter-intuitive as you go along.

First of all, people will define things as valuable if they bring utility to their lives. But the perception of value of a thing is influenced to a disproportionate degree by the perception of its availability and scarcity. Almost everyone learns this sooner or later.

We also have the dichotomy between the moral perception of a job and its salary. Most people feel that [insert should be paid more and star athletes less (at least until comes the time to pay for that through taxation). Most people feel aggrieved that they are paid less than their fellow employees in the same company just because they live in a poorer country. We see the value a profession brings and feel there is something wrong. But to the holder of the purse strings, your value is determined by the ease of your replacement, not the value you actually bring in terms of utility. Capitalism increases the speed at which this adjustment takes place, but it would still happen in a pre-capitalistic society. I would say most people, but not all, are both aware of this and inform their decisions by it, even if it's via a cultural mechanism such as seeking out hard-to-replace professions.

And there is the more insidious example that your value as a human being is evaluated not just based on how useful or impressive you are but how difficult it is to access your time, energy, and preference. You have the classic example of a person regularly brewing coffee at the workplace. They mistakenly believe that doing something nice and useful leads to being valued. In reality, their coworkers now take the coffee brewing for granted. They do not respect the coworker more than before, and possibly respect them less because they consciously or subconsciously see their time as less valuable. If the employee in question catches on and stops providing that service, their coworkers are now unhappy with them, which is the opposite of the initial objective.

Of course, this is just an illustrative example and life doesn't play out the same way every time. But holding the general belief that people will consistently respond positively to spontaneously provided services is not adaptive because it ignores social status in favor of an illusion of moral reasoning and actual utility. In fact, you could argue with the coffee brewing example that it's a case of trying to sign people on to unrequited contracts, where you do something nice and thus believe they owe you when the premise is that they never asked for anything to begin with.

In the example in the article, something similar is at play. People use FOSS stuff because they have a problem they need to solve and see a free resource to help with that. But because it's so free and accessible, there is less automatic respect for the code and its maintainer than could be expected. The key aspect is that people like Bob don't even need to be an asshole or an unreliable worker to gain this sense of entitlement as it is just a natural mechanism that does not require bad intentions. The coping strategies the article cites are all great, but they focus on the angle of self-care and self-respect, which is only the first step in the equation. The final calculus should also take into account the reality of social status and the perception of availability. You do not get treated well because you are useful, but because you are perceived as a scarce resource whether it's true or not.