It certainly sounds like you are judging. Exactly what would you "confront" such a nurse about? How is it your business to know why someone chose to be a nurse? Do you ask your doctor the same question, your attorney, your grocer, your mailman/woman, your hairdresser, your garbage man?
If you feel a calling to a particular profession and have the means to attain it, consider yourself lucky. Many people do not feel a calling to any particular profession, but we all deserve the right to make a living in whatever field we are capable. I do not feel a calling to be a nurse. I became a nurse because my previous job was outsourced out of the country with less than a week's notice. I vowed that I would never be in that position again so I chose a field in which I had some background, could make a comparable living, and likely would never be outsourced again. I provide the same excellent care that most nurses do--those who have been called to the profession and those who have not. It is very unfair and judgmental to assume I would not provide as much care as another nurse. I am still a professional and believe in always doing the best job I can, whether or not I was called to this profession with passion and excitement does not matter. What does matter is my work ethic and my competence.
I also do not consider my pay to be a "nice check," rather I consider it to be (almost) adequate compensation for the hard work and heavy responsibility I carry as a nurse.
As for taking up a spot for those who truly want to go into the profession--it's a free country--those folks are free to compete with me for that spot. If I'm the best candidate for the position, I am not going to pass up my spot because someone else has passion for the field. I deserve the right to earn a living too. If someone is that passionate about it I'm sure they'll find a way to get into a program even if it means they have to up their game to compete with the non-calling people.
Just because someone has a passion for nursing doesn't make them the best nurse. Plenty of non-calling nurses are smart as can be and work like dogs to get the job done, and I've seen some of the calling/passion nurses barely get through the nursing program and then struggle once they get out to find or keep a job. Passion/calling doesn't necessarily equal good nurse.