They will have been told countless times by various colleagues, supervisors, trainers and the Professional Standards Dept in the previous 18mths, I can also imagine that they were part of the Police family prior to signing on as PCs. The Police are not alone in dealing with people who put offensive/moronic/abusive posts on social media. No sympathy from me, the right decision, note that they are allowed to resign rather than instant dismissal. (I did 30 years as a Police Officer retiring this summer, black humour has its place but this isn’t it)