The Fi universal is that things should be decided outside of (this is going to hard to word)...other "facts". Here, I'll let Lenore Thompson say it for me:
"As an epistemological perspective, Fi leads you to take whatever a person thinks or believes as an expression of that person's unique nature--not to criticize it because it fails to live up to some externally imposed criteria like whether or not it's "logical" or "appropriate". As an ethical perspective, Fi leads you to act out of empathy regardless of the social status or "deservingness" of the beneficiary. Fi leads you to view all living things as equal in value, all needing to thrive in interpersonal harmony without giving up any of their uniqueness."
In other words, a Te world view might want to take consideration of a whole bunch of facts before ruling on a moral issue: "What will follow as a logical consequence of ruling this way?" "Did the person have a warning?" "Did the victim deserve it?" "How many people did this behavior harm?" "Did the perpetrator break a particular law on the books, regardless of whether that law is conscionable?"
The Fi world view can decide upon moral things without any of these pertinent facts. This is why non Fi users often feel like Fi users make court rulings without even hearing the case facts! To non Fi users its as if they are blind to cause and effect, "Mr Fi user! you do realize that ruling that way would create moral hazard, adverse selection and a host of other problems as a result of treating everyone equal/forgiving punishment?".
Its this metaphorical blindness to cause and effect that actual ends up being the Fi redeeming quality however. This is what allows them to simply call out unconscionable acts to our attention. The sort of acts that are simply inhumane regardless of the laws of the book, regardless of past transgressions, regardless of moral hazard, regardless of adverse selection, regardless of how 'effective' something might be. This is why selling body parts, capital punishment and exploitation of labor often come up on the Fi-radar the strongest: they are things that might be perfectly functioning in a society, be totally legal in some places and maybe even solve problems, YET at the end of the day still be unconscionable. Thats Fi.
These, "thats unconscionable" realizations are however quite rarely as important irl. This is probably why the Fi looks like they are crying wolf so damn much