This isn't really masochism, guys. Masochism is a sexual thing, this seems to be more of an existential psychopathology - something like Hegel's master-slave dialectic perhaps? (confesses to never having read Hegel).
Anywho, the problem seems to be this, which Kierkegaard provocativley put forward in the olden days: If you believe in God, because you think it is probably that he exists, because you think he seems just, that he will do good, etc. you are almost committing an indirect heresy. God demands unconditional faith - that is, belief 'without any strings attached', belief without proof, belief without reason.
Is this not the crazyness that Joanna is asking of her girlfriends? If you only submit to your husband because he's just and good, you're not wholesome in your faith. Only when you submit in spite of yourself, do you truly submit.
Why does she want to submit in that way? Perhaps because there is a certain, seemingly illogical, freedom to be had in submission, which is the freedom from making decisions, the freedom from acting upon the world, the freedom from responsibility for your actions. In short, the freedom in submission is the freedom of submitting to God-fate-husband's decisions.
This is probably quite unhealthy also for the husband because he is confronting the bizarreness of a wife that submits to whatever he does. No matter what he does, she returns the same reply: I submit, thereby revealing his actual impotence. It is impossible for him to provoke any other response from his wife, to move her in any way from her pristine withdrawal from the world.
So in one sense Joanna's position is quite proud and haughty (I am untouchable by what you do), but in another sense it may be a psychological defense against the unreasonability of being taught to submit in spite of oneself - the only possible provocation within the limits of fundamentalist, misogynist, patriarchal Christian culture?