Earlier quoted context omitted.
The only other implicit criticism toward her coworkers was ignoring and not greeting the cleaning staff. For the most part, her coworkers come across as privileged, rather than mean or otherwise morally deficient.
I'm not sure I see anything wrong with not bothering the cleaning staff while they're at work. The whole reason they've been hired is to spare everyone else the time and effort involved in cleaning, so to have everyone waste time on greetings would just be demeaning their work.
Author is describing the second, and it happens pervasively in the upper classes.