So a maximum of three alien races compared to dozens of human civilisations. That is not enough to justify a xeno-tolerant policy.
Yes, because why give ourselves the headache.
We're not operating on the rules of more optimistic sci-fi setting like Star Wars or Star Trek where we consider non-humans to be the same as humans. In 40k and in this game, if a human kills an alien, that's fine. If an alien kills a human, that's unacceptable. It doesn't matter if they're not any worse than humans on an absolute morality scale, the fact that we're humans and they're attacking humans means they need to die.
So lets make sure they don't saves us both headaches.
Besides we are more optimistic
For the love of all that is good, please remember what happened to the Dark Age humans. Instead of annihilating violent xenos, they dominated them and used them. Then when they weren't as powerful, the xenos turned on them. These aliens have been aggressive towards humans, thus they do not get a second chance and they don't get the opportunity to get used.
And if the situation was reversed we'd do the exact same thing.
Even then disregarding that you do realize that the warp storms cutting everyone off and mankinds weakness effected EVERYONE right?
If humanity didn't start lashing out randomly I'll eat my hat
The real idiots in this situation were the ancients for dominating them rather than integrating them so this could happen.
The Quartok live because they're not inherently aggressive and because the war they fought against the Imperium was purely defensive. If a xeno species is naturally aggressive or they've ever fought an aggressive war against humans, they die. Anything else is waiting for a knife in the back.
They're not aggressive, the biggest crime they can be accused of is trying to reverse engineer our tech which we forgot to tell them not to do and we then handled the fallout for quite well.
Hell they've been practically the perfect species and they're Rule of Gold idea is great for keeping things friendly so much so that Azyr a guy who literally saw humanity destroy his home with Exterminatus and hates us so much he has a trait is willing to work with us and put that aside.
Besides you seem to be forgetting a few things.
1. If aliens kill a human not of the trust WHO THE FUCK CARES, we're here to survive not dominate the xenos, when emps gets back maybe we start doing that.
2. The xenos are evidently strong enough to survive with all the ****ers around
3.
@Durin is unlikely to just have three species in one sector.
4. Its been
1000 YEARS why are you making the dumbass assumption that all imperial remnants are still anti xenos. For them its been 1000 years of hardship and trying to survive with the imperium being nothing more than a myth now, there are no consequences for communicating , trading with and allying with xenos any and if any haven't I'll eat my hat.