Its not really conflicting data though, is it? On the one hand we have quite a body of work built up over the years, of which JtP gave at least 3 examples. Add to that we do not even have a hypothetical mechanism by which a full moon could affect humans to such a degree.
Then we have one observational study, based around a sum total of 91 violent patients. These two things do not offer equivalence.
Its an interesting paper - it suggests that there is room for more research, but it is not, of itself,sufficient to cause a dent in the view that there is no link between a full moon and psychopathy, despite the link established in many peoples minds through folklore and entertainment shows...