Genocide and other Dark Plots in MG?

As the title asks. Just where is the line drawn for "dark" plots in MG? One of my MG settings happens to be a sort of dystopia. The setting in question is a bunch of various planes populated by civilizations of anthro animals and other creatures(Referred to as a "multiverse") fused together into one, single world("the monoverse") that is under the tyrannical rule of the main villain. This "monoverse" is filled with dark, gloomy, polluted cityscapes, robot soldiers, mass poverty, nightmarish factories (in the TV tropes sense) etc...There is all kinds of terrible things that have happened(Unicorns being killed to extinction(save for one) due to the dragons gluttonously consuming all of them, many of the once beautiful and kindly "starlight trees" being mutated into evil monster plants by pollution, living creatures(including the anthro-animal citizens) being used as energy sources etc..) and over the course of the story there is at least one genocide that becomes a major plot point. Also, several main/important characters die over the course of the story, and one gets transformed into a "Dark General" in the main villain's armies against their will in a rather grim manner. (Brainwashing via noxious chemicals and evil dragon magic along with some cybernetic upgrades, to be precise.)

However, despite all of this, there is no gore, and the genocides and "dark" setting are treated with a cartoon-y tone that is both true to the grim nature of the setting but also hopeful(In reguards to the fact things -can- be changed) and is at times funny/comedic and even light-hearted. If you've seen the Sonic the Hedgehog cartoon fans label SATAM the "feel" of the monoverse is a lot like the feel of Robotik-controlled Mobius from that cartoon. Even further, the cast is entirely anthro animals, robots, cyborgs, monsters and dragons. So...my question is are "darker" plots ok for MG? If so, where is the line drawn between "acceptable" and "too dark?" Any thoughts on this would be appreciated!

Ok, good to know that this kind of thing is not off limits! Also...yeah....in my case there is some pretty gruesome stuff involved(like the whole people being used as a magical energy source can get pretty horrific....and results in the death of billions....and then there is the roboterran genocide...there is also the extreme poverty of the people contrasted with the gluttonous excess of the dragons(who for the most part are the villains of the story and also a child-digestable representation of the "1%/society's privileged" that are not overly/distastefully anvilicious), as well as the general darkness of the heavily industrial, polluted, rather depressing world.

There is also some lessons about racism involved (The dragons see themselves as superior to all the other anthro-creatures because they are born with the strongest natural/inherent magical power and they (wrongfully) see themselves as having more evolved minds and thus a better understanding of the world then the other creatures.), and while there is green asops throughout I try hard not to push them too much as the green asop thing can get VERY anvilicious if your not careful. Also, in a strange twist despite how nasty most of the dragons in the story are, the main male protagonist is himself a dragon, though one who's outlook ends up quite different from some other members of his species by the end of the story. So yeah....it's good to know these themes have been touched upon before in MG!