A few hundred years ago something similar happened. The situation in Europe was terrible and people mass immigrated to a place now called The United States of America... They immigrated with no concern for the people, culture and norms already existing there, and now the sons, daughters, grand sons and grand daughters call their immigrated land for "home".Until I read through the reactions, I hadn't even realized the guy was trolling.
Intentions aside, his point illustrates the inherent difficulty the contemporary Western left has in dealing with situations like this, and why making a movement like this a thing is going to be a daunting uphill climb.
My first reaction to what he writes is, "Yeah, good rhetorical point". American Indians allowed massive immigration and they were culturally annihilated and materially dispossessed as a consequence. Why would any of us want the same thing to happen to Europe?
I don't feel any instinctive 'guilt' for what happened to American Indians because I don't operate from a harm-based, modern liberal perspective. I take a Nietzschean view--it's not good versus evil in some universal sense. It's good versus bad, where good is my civilization and the cultural values it embodies and bad is any challenge to the viability of that civilization. I have no problem at all "cheering for the home team" over time and space. To the contrary, I have a natural inclincation to do so. I'm glad Europeans won on offense in North America four centuries ago and I hope they win on defense today.
Parenthetically, the American Indian analogy can only be taken so far. European settlement in the Americas was an instance of a more demographically numerous, more technologically advanced civilization settling in a relatively undeveloped, uninhabited land--which, in the case of North America, couldn't really be considered a civilization in any meaningful sense of the term--and which the success or failure of said settlement was almost entirely determined by the invaders, not those being invaded.
The MENA invasion into Europe, in contrast, is characterized by far less advanced and less numerous (at least at this point) peoples coming into a civilization that can very easily repel their settlement and render it unsuccessful if they elect to do so.
A better analogy is the massive Gothic invasion of imperial Rome during the 4th century. The Romans had the capability to keep the Goths from crossing the Danube but chose not to stop it.