Do you think those who optionally exercise the mental activity of making judgements of those behaviours are likely to suffer more or less burnout than those who choose not to? How useful an activity do you think making judgements of people you interact with is? Who is it useful to? The judge? The judged?
Not everyone exercises perfect control over the activities of their mind, and not every thought is carefully selected for optimum results before thinking it.
The point is just that even altruistic people, who one might presume are disinclined to such judgments, can find themselves making them after a time.
Besides, the doctor in my example was not even judging people, merely expressing exasperation at the inability for the resources expended to hit their intended targets. No one likes to feel like their work is meaningless, and getting paid (in public funds, no less) for patients who don’t show up might feel meaningless.