Because we did bad things to everyone else in order to now be better off than them.

What did white people do that any other race didn't do to eachother?

If africa won the colonialist lottery and ended up in western europes position, it would be more or less the same situation. Youre not wrong but its not that relevant.

Estonia never colonized anyone, we were subjugated for over 700 years, yet, since gaining independence, even before joining EU, we more than doubled our GDP in less than 15 years. We won no lottery, but we managed to be successful on our own achievements only. Why does EU makes us feel like we have to share the burden of immigration and refugees?

Its not, its wrong that you need everyone to be white for it to be homogenous.

It's no secret that there's less crime in more homogeneous white societies, that there's more trust and cohesion. It's no secret, that with refugees and immigrants there's increased crime and many other social ills. Why should I accept even 0,1% increase in rape, murder or theft to accommodate people who's ancestors didn't have to sacrifice their blood, sweat and tears to create this place?

What does that even mean? Which cultures are incompatible with yours?

Islam is a prime contender, they hold pretty much opposite values we've held for thousands of years. Why can't I say that cultures that believe women are worthless, that hold a god we don't believe in closer than their fellow men are not welcome?

Those two things arent connected. your people will continue regardless of the colour of their skin wont they?

Again, I'd like to bring the muslim example. They have far more children than us and they are very devout in their religioin, they will never become Estonians and they don't want to.

arent richer countries doing the same thing?

Yes, richer countries are doing it, like Sweden, which has lead to heavy decrease in their HDI, PISA scores. Major increase in crime, especially rape, murder and theft. If Sweden who has a shitton of money can't figure out how to coexist without these social ills, how could we? We don't have the resources to accommodate refugees or immigrants, there isn't a chance we would do any better.