The ethics of ethicists

In Do ethicists steal more books? (Schwitzgebel, E.; 2009) the author recognizes that no impartial research had been done on the ethical standards of professional ethicists. Therefore, he conducted studies to discover whether books on ethics will be missing from academic libraries in a percentage less or equal to the ones on topics in philosophy and not on ethics (philosophy was chosen to keep the focus disciplines close). The answer is no, professional ethicists appear to be more likely to steal (or borrow for an indefinite amount of time) books than their academic counterparts in other fields of philosophy.

The study goes against the Aristotelian concept of ethics, where it is studied not for its theoretical understanding, but in order to become good. This brings out the question of whether the study of ethics is something that will improve on the moral
behavior of students, or quite the opposite. Prior to this research, the ethics of ethicists was examined only in controlled environments, where the test subjects were more likely to be biased toward more ethical behavior, conforming to expectations.

An interesting research paper on the ethics of economists is mentioned. This study shows results that indicate that economists are generally more selfish than other people — not because studying economics makes them more selfish, but because those who choose to study for a career in economics are already more selfish than the average person.
Does this mean that there is a chance that ethics is studied by those who are more morally corrupt than others?