You guys forget the Brie is basically a newborn with all the moral quagmire that entails with that sapience,and she had to gain this newfound morality in the middle of a Grail War where the players have already hardened themselves to sacrifices.
Brie isn't hardened. At all. Up to now, Brie was lucky to face opponents who were relatively nice (Hans, Master of Caster, etc) or people who you don't feel bad when their faces gets caved in, and she's been pretty good at minimising casualties on her own side thanks to early police surveillance. Now, with what Emergency Brie did to Olga and the resultant reaction from their next meeting and the revelation that Rider may have accidentally oopsied a few innocents during her 'patrols' , it's clear that Brie isn't ready to take up the responsibility of eliminating morally ambiguous individuals and her consciousness is taking a beating.
A good long talk on what her priorities should be, how she should feel about the recent incidents and how she should handle her guilt is a long fucking time in the making and not some 'high horse we should get off'.
The crux of the issue is that we've hit a fundamental fact of Brie's early-game strategy: Momentum had to be kept.
We eliminated "more" Masters because Brie got the strategic and long-term help assistance options and rarely took the option to withdraw from a fight. But after we beat Hinako and Frankenstein, things slowed down. Kiara got Olga off-screen. We got involved with Hans, Shishou, and did Medb-buli. Right now, our only solid piece of progress that remains is the elimination of Caster. The police, while only marginally relevant compared to Kiara's cultists, are about to enter the phase where they're only good for helping a write-in of "evacuate the city".
Brie's struggles were in the name of
ending the fights as quickly as possible. And it's 90% been for nothing.
The last vote options were A. Puke in a bin(which we picked) B. Deny the actions done during our Mecha-Brie persona are our responsibility(and phrased in a way that screams Bad End Flags), or C. Try to deny that Medb did drain people to death.
Or D. The write-in about Medb and Kiara's dalliances having ominous implications. But turns out Kiara wasn't sending Rider over the edge and out of control.
Meanwhile, Olga Marie is all in our face with her mental breakdowns, serial murder and whatnot, that's why this whole episode is so contentious.
No, this isn't contentious because of 'in your face' problems. It's contentious because 1. A previously 'safe' behavior method known to the players is now revealed to have been false. 2. It's something that fundamentally has no easy to understand solution.
Think back to my last post: Medb lied to us because she is incapable of changing who she fundamentally is, as a Heroic Spirit. Yet she knows that Brie accepting the deaths of innocents is going to destroy what she loves in Brie. The only people to rein Medb in and make her behave are other Heroic Spirits. So, on the surface, the only ways to solve the issue seem to be either performing a deed worthy of becoming a Heroic Spirit ourselves or altering Medb's life-granting Wish on the Petty Grail to better put her in a position where she can change as a person. These both have a problem of being
end-goals, not things to be done now, and especially not things which solve the problem now. And I'm not even touching the disturbing fact that
Medb chose to use our poor prana-supply situation as a metaphor for our romantic relationship. 
