I could be wrong, and I’m sure I’ll be pilloried if so, but I don’t think the ‘stolen land’ part is really the point of the statement. To me it’s more about pointing out the difference between ‘undocumented’ and ‘illegal’. In the same vein as ‘unhoused’ vs ‘homeless’. Or the classic ‘tomato’ vs ‘tomato’. To me it seems to get lost in pedantic weeds and I prefer the Shakespeare observation of a rose by any other name.