Gaining influence with Kreia was pointless and nearly automatically meant losing influence with all the other NPC because she's an expert in annoying everyone. As what she had to say in the dialogues that required influence checks didn't matter much, well fuck her.
Also, she's a villain, plain simple. Not in the SW sense but still a villain. She wants to destroy all of the force and wanted to kill both all the jedi and the sith, she's even more dangerous than the sith themselves (not the "ancient sith" crap we keep hearing about but never actually see).
If you play dark side you may not realize that she tricked you so you could let her kill all of the remaining jedi, which she does with her own hands when you are light side and let them live.
The sith just want to rule over an empire, Kreia dreams of mass murdering force users, who are the real villains ? Malak is a power hungry fascist, Kreia sounds like she wants to genocide just because she suffered in her life as a force user.