Why didnāt anyone tell me Sannanās route was the one where Kaoru gets to kill Kodo with extra prejudice for what he did to him (and to Chizuru to an extent, even if Kaoru reaches once again the wrong conclusion)? I would have blasted through it!
Maybe it's just my white German guilt speaking but I think we shouldn't, perhaps, forgive racist, eugenicist, genocidal Kodo for what he did, even if he's our/Chizuru's father. (Even though the games clearly want us to.)
Filial piety be damned but having empathy with perpetrators at the cost of acknowledgment of the damage they caused and the people they victimized is immoral in my honest opinion.
Also, from a writing perspective: Having Kodo as a morally plain-bad villain representing the "evil scientist" stereotype in multiple routes makes a redemption or even just empathy for him difficult to achieve. Same goes for Sannan but he at least gets a better chance to be understood in his own route.
(Like with Star Wars: Darth Vader's sacrifice in Ep. 3 of the original trilogy doesn't really work if you haven't seen him as Anakin Skywalker and witnessed his journey beforehand. And even then it's hard to empathize with him at all because of all the atrocities he's committed.)
Kaoru might be easier to forgive or at least empathize with since we know that he's been heavily traumatized since childhood and never was able to recover... But empathy for Kodo is prioritized in EB which can be seen in the several times he's sacrificing himself to save Chizuru (which likely serves as an effort to redeem his character).
It feels similar to the Eren situation in Attack on Titan and might portray a pattern in Japanese media/society in so far as they acknowledge the crimes committed (that mirror Japan's colonization and war crimes in WW2) to a certain extent but still empathize, even sympathize with the Japanese perpetrators while never doing reparations, apologizing or acknowledging the harm they caused to the full extent. More attention is given to the "despair/emotions/thoughts that led to" the perpetrators committing the crimes than to the repercussions and the victimized. Again, this is highly immoral.