In the weaker, first interpretation no migrant or their descendants can truly ever become Austrian, unless they are ethnically Austrian. They will be tolerated and treated equally under the law (as cultural-Austrians), for as long as they conform to the culture (which means participating in language, traditions and customs). The same is true for their children, unless they are above a certain percentage of "purity" to be considered ethnically Austrian. At that point they, just like other ethnic-Austrians are exempt from the necessity to participate in traditional culture, and can actually shape culture / redefine it and express themselves freely. So the traditional phase of youthful rebellion against the norms and traditions, as is the absolute standard might lead to a deportation for the children - depending on how strict the conformity to culture is seen.

edit:

In the weaker, first interpretation no migrant or their descendants can truly ever become Austrian, unless they are ethnically Austrian. They will be tolerated and treated equally under the law (as cultural-Austrians), for as long as they conform to the culture (which means participating in language, traditions and customs). The same is true for their children, unless they are above a certain percentage of "purity" to be considered ethnically Austrian. At that point they, just like other ethnic-Austrians are exempt from the necessity to participate in traditional culture, and can actually shape culture / redefine it and express themselves freely. So the traditional phase of youthful rebellion against the norms and traditions, as is the absolute standard might lead to a deportation for the children - depending on how strict the conformity to culture is seen.

Deportation of children? And this is your weaker interpretation of alt-right Austrian views? Can you really not imagine any other way to preserve Austrian heritage?