Well morality and empathy are clearly not the same and the 2 clearly link to your social environment
i mean just look at the slave trade and all, the traders where people with empathy to other in the same class as them and probably a sense of justice, but if you where not from the same class you where below trash.
And i mention justice, justice is also a part of the problem, justice is a social construct just look at twitter and how their sens of justice differ from more well rounded people and for tifa, yes killing the bad guy is justice for her, like a lot of people in Murica think dead sentence is a good punishment but also think killing is bad, everyone has weight the good and bad differently and all have a personal balance, and all is influence by the parent, the emotion they fell and juste social interaction
So yeah i don't think Tifa is a well balanced, and she is stupid to my eyes, but i think she is a good character, and the author probably know all of that and will make her learn lessons (and that way more interesting that the all to common "perfect people" in manga)
by the way if anyone did read HxH here, Gon is way worst that Tifa when it come to "justice" and empathy but it's also one of the best written shonen MC.