Perhaps, we are more in-tune with how others' behavior makes us feel in this field (some, not all of us of course). Combined with the fact that we have a framework for discussing patterns of behavior and how they make us feel, we might be more inclined to label someone as having a particular PD or other diagnosis. Taken a step further, we are in a helping profession, so we might then feel like it is our responsibility to "help" this person, or to alert others who will come into contact with him/her.
Maybe I'm about to make this way too simple. However, as someone who took a significant amount of time working in non-psychology fields prior to entering graduate school, I found that there are jerks in positions of power in all different fields. We call it BPD, others might just call it being a....well...you can fill in the blank. Either way, you will find them in most settings (psychology or not) and I think the key is learning how to work with them and not to lose sleep over their behavior.
Maybe I'm about to make this way too simple. However, as someone who took a significant amount of time working in non-psychology fields prior to entering graduate school, I found that there are jerks in positions of power in all different fields. We call it BPD, others might just call it being a....well...you can fill in the blank. Either way, you will find them in most settings (psychology or not) and I think the key is learning how to work with them and not to lose sleep over their behavior.