I think that to me, I think of each person's responsibility being to take care of themself and their own actions, speech, and behavior, but I'm not very well-attuned to gauging how other people would feel about things. When my little brother struck up a conversation about smoking, which is illegal where we live and not explicitly approved of by our parents, I responded, but I didn't really think about who might be around to hear. He started the conversation, and he's the one committing the "bad" deed. I don't see it as my responsibility to protect him from any fallout from either of those things (though I would like to help him, since he's my brother). Still - not something I have a moral obligation to do.
He, on the other hand, was infuriated that I wasn't keeping an eye out for him. He thought I was deliberately messing him up, being stupid, and being careless. IMO, if he was concerned about people hearing, he shouldn't have started the conversation in the first place. But to him, I think he assumes that it's part of interaction that you attend to who's around and adjust your volume level accordingly. He sees that as a moral obligation, while I don't. In contrast, he has no problem mocking my character, which I see as a "serious" insult, while he sees it as an insignificant one.
So I think Fi puts more value and more weight on judgment of the self and personal freedom - one's character is to be measured. Fe seems to put more value and more weight on judgment of action and interpersonal cause and effect - one's behavior is to be measured. For Fi dom/aux and Fe inf interacting, this can mean that the IxTP accidentally insults the FP's character while the FP accidentally makes the IxTP feel exposed. Many F rules are "unwritten" but we hold transgressions against each other because we think they indicate intention to harm.