Actually, Sapphire, the setting is unintentionally made grimdark, but violence isn't the issue. The issue is KCs poor worldbuilding skill, several different techniques and POVs of storytelling mashed together in a single mess and the outright fact that his statements disprove what was sad and shown in setting and the published material. Also DE.
If anyone says there is no mindbreaking, then they are in denial. I will point them to the canon fact monsters with Druella giving us 'on screen' (on paper, actually), undeniable proof of that when she rapes women despite them outright protesting, then in the classic hentai twist It starts to feel good and once they starts cumming they are suddenly fine with it out of the blue.
If we are objective and fair with MGE as with any other piece of fiction we tend to rip apart for minimal shit everyday then there is no doubt that MGE when looked at a literary formatted whole is horseshit. Bad writing and inconsistencies should not be pardoned just because we like parts of the work. KC is master at making Monstergirls, but his world is a jumbled mess, crammed with all sorts of plot holes and devices and various inconsistencies because they are cool even if they do not go well with what's already there.
As for DRS, imagine using it on a Valkyrie. What you just did to her in this what if scenario is unforgivable and outright wrong. You tainted her with DE, against her will, most likelly alienating her from her friends and family as she is no longer capable of going into Heaven's Realm.
If we go by how it all works in world, without our beyond 4th wall cherry picking of facts, feats and statements, then there is lot of morally and psychologically dark happenings in the MGE world which DE will magically fix, even if it's the minds of the people.
I once compared Aschens from Stargate and the DL. Their agenda fits the DL's to the T, their motives my be different, but in the end, doing bad and evil things in ignorance or by mistake while trying to do good doesn't make it any less evil or wrong no matter how you look at it. If we want to be honest with ourselves, the DL did genocide several species, already but no one blame her.
That's why I'm a Neutral, Infinitely more powerful 3rd party than siding with either DL or the CG in my take of the story here on the site, Yet I will help the little people, the everyday folks and average Joes and Janes in need regardless of their affiliations and species. Dl and CG both suck and are flat out in the wrong, the true peace is right in between yet they seem not to see it from all their 'superior morality' and avarice. They both live their luxurious lives while sending their poor underlings to fight wars for causes they don't believe in and reasons they don't understand.