In actuality, it isn't as bad as everyone makes it seem.

According to the Lady Skorri's grimoire card, she is writing the iron song and is discussing everyone's part and talks about including Efrideet into the song but can't figure out how. Not only that she hasn't been seen in weeks so she doesn't think she will get a line in the songs.

One can assume that this song is made right before the SIVA Incident. Meaning that her story of being away makes sense. Not only that, I forgot who, but someone mentions that Efrideet is a pacifist.

Also in her quest line for IB, she talks (you read it) about her experience with being an iron lord and how she, and many others, left to use their light in non-violent ways.

She eludes to this even more by the 3rd (and final) quest you turn in (rank 5). She talks about maybe she will take you there someday to see those other iron lords she left to be the rep for IB.

Tl;Dr bungie does a good job at sorta fleshing her out, but it does require you to not skip her text and read grimoire. Hopefully for Destiny 2 they just integrate a journal to in game.