I'll take that at face value.

> If what you quoted is the dog whistle, what is the decoded message that the in crowd would be hearing?

Both tie closely into bog-standard reactionary and white nationalist rhetoric. The first is a dogwhistle for "the great replacement," or the conspiracy theory that Europeans (meaning, to them, whites) are being intentionally replaced by migrants as a method of control. The latter ties closely to a crowd that calls themselves "white nationalist" but not "white supremacist" -- they insist that they don't believe in the superiority of whites, and only want isolation for "fundamentally different cultures" (by which they mean races). It should be apparent that this is really just white supremacy with more steps, especially if (as this introduction proposes) the European continent functionally becomes the landlord and benevolent overseer of a migrant nation.