When you say what rule was broken(as in the case of Sam) they say ok and move on.

People only argue it when they don't think they've broken a rule. People argue when they feel like you've deleted a post more because you personally don't like it rather than it was a legitimate violation of the rules.

Posting what rule is broken will not only make you mods appear to be fair in upholding the rules it will serve as a good reminder to people what the rules are and that violations will be acted upon.