I am not aware of the details of the investigation or of all the circumstances that informed this decision. What I can say on this is what is on the public record, which is that the seriousness of the offence is one factor but is not the only factor in making the decision to prosecute or take other steps, such as a compliance agreement. The commissioner has been explicit on that.
One factor, for example, is the availability of evidence. Is there evidence that could support a criminal prosecution? If there is not such evidence, then that's the end of the avenue for prosecution.