New Zealand has much stricter filters for immigrants.
Tautologically: good immigrants are great and bad immigrants are terrible. I certainly know a few awful immigrants too.
30% of our population was born overseas. It seems to be working fine for those born here and for the immigrants.
Young New Zealanders emigrate, and existing immigrants get older so NZ has an ongoing need to have more immigrants.
People want to come here so we have the luxury of setting filters. I'm not sure what will happen when other countries start competing harder for the "better" immigrants.
Australia is similar but it has less trouble with losing its young people - it gains a lot of New Zealanders because it is a wealthier country with better weather (but bitier fauna)
In the 19th century China enjoyed such an abundance of labour that they felt little need for an industrial revolution. By shovelling labour into developed countries you are depriving them of the impetus to innovate. It will have terrible long term effects.
There is no law of geopolitical physics that says regime change operations must be confined to developing countries. In the event of a serious deterioration in US-EU relations you shouldn't expect the US to sit idle. The European far right does not care about Greenland one bit.
We could very well end up in a situation where we have the US and Russia working together to destabilize the EU, perhaps European leaders fear this and will let Greenland go.
55% of the 1 million Syrians living in Germany are dependent on welfare.
The act of immigrating on its own does not select for anything other than a willingness to relocate.