The families of the millions of innocents that she casually knocked out of the way just activating her weapons (which she did not in any way have to kill - she could have evacuated and warned them if she chose, but they weren't worth the effort to her) don't care what her good intentions are.
And it may be just a video game, but fictional stories have a powerful ability to preach messages that people will actually listen to. Which is why the creators of those stories need to be very careful with them.
^Speaks great truth. I wonder how many clichéd sayings people will just nonchalantly throw under the bus to defend someone they've become attached to... or better yet perhaps... someone who has done something that is inexplicably out of character a la poor writing?
"The road to hell is paved with good intentions". That simple statement speaks volumes that people just seem to toss in the trash. I mean, even Forrest Gump understood what Mama meant when she said "Stupid is as stupid does," Replace stupid with evil and the concept remains. Powerful statements that have stood the test of time and they've done so because "Actions speak louder than words".
I threw this challenge out here once before and I'll do it again. Take it seriously, there's no sense bothering if it's taken with the attitude of "Meh, fine, I'll play along".
Imagine your entire family and circle of friends live in one region. They were all home except for you. For some reason, you were off planet when one of Cortana's guardians activated. Imagine everyone you ever loved or knew were gone, just like that. Imagine visiting them at a mass grave. Maybe it's just a memorial, since likely their bodies may never be found. Know that their deaths were likely horrific. Buried in collapsing structures, crushed by falling debris, shot down by Prometheans while simply trying to escape. Stand in front of them and explain how Cortana is "not evil". Use all the standby arguments like "not really... she has good intentions" - Tell them "It's possible she's just sick... or defective, we don't really know". Close your eyes, run your fingers over their engraved names and say to them "She's not really evil, she's actually trying to do the right thing... just in the wrong way".
Now ask them if it matters what her intentions were. Ask them if they feel better now, knowing she didn't really mean it. Do let me know if you ever get an answer from the silence.
It's not about intent, it's about impact. Impact is tangible. Intent is worthless in comparison and it can be lied about, manipulated and made up as it goes.