There's a thing though chaos gods are not those type of deities because Khorne can claim to be the spirit of bloodshed but the Emperors been around killing people in glorious melee combat longer than Khorne has existed. The chaos gods are false in most ways they can't claim to be the spirits of change, hope, magic, Bloodshed, violence, Decay nature because we know they are explicitly killing or holding (Isha) the actual spirits of those things. They also make claims of being all powerful being the masters of Fate being in the actual things that control the universe and all of those are also false.
So the chaos Gods aren't World Spirits, they aren't actually the spirits of Concepts. They are parasites essentially if you were the emperor you would see them that way because you know bloodshed existed well before Khorne ever showed up on the scene you knew Excess was a thing well before the Prince of Pleasure ever showed up you knew Hope was a thing before the mollusk ever showed up you also probably knew Human and Eldar gods that definitely were around and were actual spirits of those things before the chaos gods showed up.
The fact of the matter is the Emperor because of his position in the setting we don't know what he knows but we do know from information given to us by outside views that the Sea of souls did not contain the chaos Gods initially and this can be confirmed via both text and research from the old ones which he possibly could have possessed because he was building a webway and we know the Eldar didn't make their own. He's not old enough to remember Asuryan's edict that separates Divinity from Eldar but he definitely had a 15,000 year overlap in time in humanity space exploration age to learn about such things. So it's literally impossible to know what he possibly knows.
So from his perspective we know that they are not immortal they are not the spirits of things or concepts they are not necessary for those Concepts to exist they are not personifications of Concepts they aren't World spirits and they consume The Souls of beings in the warp so they fit the criteria of demon or otherworldly parasite at best but fail to meet any possible description of divinity. In all seriousness if you believe in any type of God or gods animistic or otherwise you should not think the chaos gods are deities. They profane corrupt and destroy everything they come in contact with they lie and seduce and manipulate at every opportunity they cheat with their word and deed. Even under the loosest definition of divinity they are not divine.
The idea that Humanity inherently deserves the Galaxy is a bit of propaganda that I feel gets glanced over because it's very obviously a lie. He's building a webway gate on Terra. The goal is to unite Humanity. It's more likely that he actually thought this galaxy is fucked and if I don't do something humanity is also going down with the ship so he spits that bit of propaganda to get every human-aligned faction under control then he starts building his web way gate and then because Humanity at the height of the age of Technology outright had technology capable of moving stars and planets it's probably make webway, take humanity and all its worlds into webway, say goodbye to fucked galaxy.
Sorry this is insanely long but I will close it out like this if you were a peer of these beings and you saw them come into existence I imagine it's really difficult to think them at all Divine even if from a normal human perspective they would be. To you and your ancient powerful gaze they are not amazingly or overwhelmingly powerful they are not the concept that they represent they aren't actually the spirits of those things and they are seemingly pathological Liars scrapping each other endlessly for a game. I imagine it's rather difficult to see anything other than malfeasant warp energy when he looks at them.
