Sine the betrayal is very much a fact, Moran is still angling with finding out her motivation and if she betrayed him on purpose or by force, and maybe also what happened to her after that in more details than just 'she buried their bones' (apparently not very well, since, well, ghosts).

It just bothers him to have heard only one side of the story, which is basically 'witches bad, don't trust women'.