She did assume he felt like she does about Dwarven customs.

In her defense, the only Dwarf adventurers that we have seen (unless I'm wrong) are Durkon (special circonstance), herself (chaotic) and Kraagor (barbarian so a priori not lawful). So it seems that very few dwarves, let alone lawful dwarves travel in human lands if that is the case, Occam's razor would justify her assumption.