The towering spires of Hive Cities and pristine halls of Shrine Worlds are our art, crude, cold but ours.
Towering baroque spires and pristine halls of the shrine worlds... Crude? You aren't one of those fancy Eldar are you? :
P
If the Imperium is humanity, then humans aren't worth saving.
If humanity is humanity, humanity doesn't deserve saving. Not going to stop us fighting tooth and nail to survive, because the human spirit is to persevere under hardship, to keep on and never stopping
Better let my own race be assimilated into a larger empire than try to maintain hegemony over the galaxy at the price of everything that makes us human, yeah.
Roflemao
The Tau are a smaller, much smaller Empire (their entire species is outnumbered by a handful of Hive worlds and would fit inside the Ultramar Empire inside of the Imperial Empire), so destroying your own race just to avoid any self sacrifice seems like a pointless surrender of everything human in order to appease the Ethereals and get holowaifus whilst your species dies out to a brave new world
Fear, brutality and bureaucracy, all parts of humanity right there. Hatred, contempt and struggle, really freaking human right there. In the 41st Millennium, perhaps the only thing not of value lost, is modern "art". Oh and there's beauty, it's the most human kind. Men and women sacrificing everything so that men and women elsewhere can found their own families, continuing the cycle onwards for the Imperium of Man, of rusting relics of a bygone era flying on wings of steam whilst the elite adorn themselves like South American birds! It takes creativity to not perish, and you can never erase the beauty of the human face for as long as it has eyes to see it - and the future of the 40k universe is often so bright, you don't even need your eyes to see it. Even Ogryns too carry the beauty of their souls, personality over appearances it seems, for you strip away baubles and trinkets of shiny gems to see the beauty that is humanity.
Doom is certain, guaranteed, by the oldest definition of destiny. There is no avoiding it (at most delayed), progress a delusion founded by those who take the view that there is a right side of history, that everything is on a progressing path to utopia - when it is a cyclic expanse of rise and fall, of ages that are winks in a grander cosmic war, whilst us as living thinking beings walk on to certain path to extinction. To diverge and bring a real world analogue to this fiction, it reminds me of old Saxon poems, how in old England they would make their hovels atop abandoned Roman ruins, ever cognizant that the end would come for them too - looking at the remains of an ancient advanced civilization that they inherited the corpse of. Or how the Buddha would tell you before he left Princedom, how of even the greatest mountain an end must soon come, as all things are impermanent. The world of 40k is like that, everything falling apart, held together by the duck tape of immeasurable sacrifice, all to keep the cogs turning. Mankind worships a God of stagnancy, one who is doomed to die, upon whom all efforts are wound - all for the hope of a few ten thousand more years of man, before the cosmic beings once more take their ascendancy from the War of Heaven or in a new age of Chaos.
There is no veneration of man's own arsehole, there is only veneration for the Emperor, humility the law of man in service to a God whose every waking moment is agony for being called such - a most reluctant God, who
But has to, because that's now his job. Maybe you'll be unlucky and before you can show your love for that special someone who'll make you part of a family, one more link in an innumerable chain of parents, you'll find your planet overrun with one of the apocalypses of the day. Maybe it came from within your government as a result of Tzeentchian cultists, or maybe the sun has been blotted out by mycetic spores, or light years away a cthonic death engine is harvesting your solar system.
In that case, you won't get to love much. You probably will be the end of your chain. You've been doing your job because you had to, and now it seems you have a new deadlier job that will ensure if you die, the buck stops with you, for even in death duty does not end. You couldn't choose to be born in the dark age of technology, couldn't choose to be born to paradise world elite, couldn't choose to be born on an angri-world family or the scrummiest siege world, but you can make your death give meaning to the lives of innumerable people in solar systems far away - if you choose to die standing.
Thus battle brothers, sisters of battle, guardsmen, militia, PDF, civilians, gangers and coppers, miners and bureaucrats, engineers and enginseers, all play their part to ensuing the song is sung just a little while longer - a few ten thousand more years, and we'll see how things are after then. By the light of the Emperor; even such light will one day give in to the void. Until then, there is Mankind.
I do like how even the Mechanicus, who replace all but the most vital of human components - our biological computer, are demonstrably human. The fucking nerds speaking in binary in the sekrit club, sperging over tech and dorito stained mechadendrites, one of the more heartwarming pieces I've read in 40k was a tech priest recommending his battle servitors for chapter honours for having done their bit with his last dying battery.
It is not that it is evil. It is that it is pointless. Were the Imperium to lose, nothing of value would be lost. It is only that the humans who are not subject to the entirety of it's weight might die, and the galaxy itself and all of the beings in it would perish to whichever threat was most dominant at the time.
Were the Imperium to lose, mankind dies. Everything of value would be lost.
The Imperium is not humanity. The Imperium is simply the majority of humans, stripped of their humanity. They are cogs in a machine, nothing more. There is no meaning to their existence. There is scarcely more in their death. It is survival and hatred and longing for a past that once was. It is not the humanity I love.
The Imperium is not humanity, humanity is trapped in the belly of this horrible machine, and the machine is dying. There is no way out, because if you break the machine, the maelstrom outside will flood the machine and kill everyone.
Thus humanity holds onto every last shred of humanity, every inch of ground given at terrible expense to those around it, in order to ensure each human chain continues for as long as possible, so that from the eyes of this terrible machine mankind can see the beautiful sunset before everything goes dark.