Ethnic cleansing is the systemic forced removal of an ethnic or racial group from a given territory (by means of violence or persecution). No goalpost moves needed.
It seems I have made a serious mistake. I've always been under the impression that ethnic cleansing was synonymous with genocide. I had no idea that deportations only could constitute ethnic cleansing. That invalidates some of the earlier points I've made in this thread.
Then I'd like to rise to your earlier challenge: Your challenge was:
How about you find me an example of a nation state with the ethnic diversity of France or Germany successfully making the transition to a country with the ethnic diversity of say, Japan, without resorting to violence or persecution. I don't think you can do it, and I think you know it.
I think the reverse is mostly true too: you don't turn a nation state with ethnic diversity of say japan into a country with the ethnic diversity of france or germany without resorting to violence or persecution either.
If you get technical, anything that a state chooses to do, including raising a tax or creating a new one, is rested on the implicit monopoly of violence that the state has. If people go along with it peacefully, it may seem non-violent, but that is as much the case for deportations. And if resisted, then it leads to employing state violence.
We are living in one of the most peaceful times in history. Certainly there are many deep problems and there are war and conflict ridden places in the world, though compared to nearly any point in history, people are far less likely to die as a result of conflict.
This would mean that peaceful solutions to problems are more likely than they have been at any point in the past.
Take for example catalonia. They declared independance after a referendum last year. Spain did not agree, imprisoned several former ministers on charges of rebellion.
Now if the spanish government had not challenged this claim of independance, it would have been a violent-free creation of a new state. Now, I don't think it's very likely for any state to just let an independance movement go (militarily) unchallenged, but any such violence is the result of denial of people's desire or right for self-governance. And independance movements or rebellions become more likely the more that a state does not address the things that people desire the most from their government.
And if the desire and willingness to defend their independance in the case of catalonia was bigger (the referendum's result weren't clearcut from my limited knowledge about the subject), or maybe if they had gotten the backing of a foreign state that would promise to protect their independance, spain could have decided not to challenge the independance claim.
Now then, Catalonians, if they still desire independance, are forced to figure out a military way to get their independance, because a peaceful path would not be accepted.
I think a similar thing would be true for any would be ethnostate, whether currently existing state or result of an independance movement. If sufficient people desired it (and I don't think anything close to enough people desire it to have any appear in the next 3 decades at least) and they prepared for it and sufficiently powerful support, there would be a peaceful path. Of course people are unlikely to give up their power and any country that loses a part would immediately fear for losing a second part and would try to make an example, the way spain made an example of catalonian leadership.
And this refusal of accepting peaceful means, means that when the desire for an ethnostate has grown in any area to sufficient critical mass, it can only be violent and it is more likey to have a genocidal ethnic cleansing rather than a peaceful one.