I am tired so I won’t be able to make a too coherent post now, but here is a link to wikipage explaining largest mass deportations that have been done. Note that it was aftermath of WW2.

As general rule I don’t think mass deportations are good thing. There may be exceptions, but at this moment I am too tired to think of what those exceptions might be, if any. I do think that deporting criminals is good thing and my country does that - after the criminal has served the sentence of course. But, that is different thing than mass deportations. Completely different thing.