In a globalized world, not only are labor and markets shared, but so is suffering. It's only right that if other countries' inhabitants can be targeted as consumers, they should also be welcomed as guests in extreme circumstances.
assuming that at certain points in human history breakthroughs are going to happen that vastly increases the quality of human life on Earth. Diverting resources to take care refugees would only slow down progress and indirectly cause more suffering on Earth or even extinction(not leaving earth).
I'm not sure what point you're trying to make here. If you're trying to say that refugees are a consequence of imperialism, that makes sense. If you're saying that imperialism is a good thing then I think we have a disagreement.
I generally think imperialism is a good thing, especially if it leads to free migration which the point makes. I guess what I am arguing is that it is good and right when refugees from undeveloped countries flee to developed countries.