Edit: Blocked the author's name, because it's not my tumblr. I didn't expect so many people to misinterpret it and respond in this way.
Edit 2: This is not from the same author, but it's a reply to them. I think it might help clarify the post for those that are confused:
I normally don't worry about usernames on tumblr, but since there've been some really out-of-pocket misconceptions in the thread, I don't want anyone to harass them.
You can say that about pretty much any nation on earth. We humans have been migrating for as long as we've existed.
But after how long does one become 'native'? Most ties to the original country pretty much disappear after 2-3 generations.
Becoming "native" isn't as simple as not having a culture. It's having a culture specific to the region. Settlers never develop this because they believe that not having ties to a region and exterminating those who do is sufficient.
Becoming native historically has generally meant adopting the language and customs that evolved in the region, or staying in a region long enough to evolve customs and culture. That takes several thousand years.
But there are also both nomadic and diasporic people. The existence of nomadic people is directly threatened by the existence of borders, making borders, in and of themselves, a tool of genocide. Diasporic people are not native but also not colonizers. Antisemitism is one example of persecution of diasporic people, while ant-black racism is another.
We have been migrating for thousands of years, which kind of invalidates the legitimacy of borders and by extension countries. If the existence of a county requires a border, by definition, and borders are genocidal, by definition, then countries are genocidal by definition. If we accept that genocide is a bad thing (perhaps the worst thing) then how could we accept the right of any nation to exist? At the very least we should demand the abolition of all nations that exist within the same space as nomadic people.