So too the cityguard decided to attack the paladin. Cityguard's choice. He could have recognized that his service to the Spire was, on the balance, serving the ends of the wicked and stayed his hand. He didn't, and ended up paying the price. Or, failing that, he could have realized, "There is absolutely no point in me attacking this paladin because it will only result in my death." But, zealous servant of the Spire that he is, he attacked anyway.

You seem to want to lay 100% of the "blame" for the encounter on the paladin. To me, that represents a somewhat OOC awareness that the mob is a "mob" and can't make decisions on its own. In the context of CF the mob is a sentient being who can choose to attack or not to attack.

btw, would you fault a fortress-minded young adventurer for choosing to study conjuration because it might bring him into conflict with a good-aligned battlerager or outlander who might, in the course of that conflict, die? I mean, it was the young adventurer's choice to study conjuration, right? He could have become a healer instead and avoided the conflict altogether. It's not like he didn't know battleragers and outlanders existed before choosing to study conjuration.