How does that differ from me saying that I can prove ties to Germany, therefore I should be able to return to Germany? Because I can (g-ma on mom's side was 1st generation American).

Because we're not talking about whether you "should" be able to return to Germany. It's about whether your returning to Germany could be considered colonization. Germany doesn't have to let you emigrate to Germany - but if Germany adopted a policy that folks with direct immediate German ancestry were allowed to emigrate to Germany, we would not describe that as "settler-colonization."

The only difference I can see is that the Torah says that god says those lands belong to the Jews.

Again, this is not dependent on a religious argument. Irrespective of what the Torah says, the archaeological and historical record is irrefutable that Jews are indigenous to the area. We're from there. There are plenty of zealots who also point to the Torah for their claims....but there's no dispute about the historicity that the Jewish people originated in the area.