Cruz is talking about legal immigrants, who will follow the law. Of course we should enforce existing laws, which would require that every illegal must be deported. Sadly only Tancredo will do something like that.
Cruz would be reasonably accused of hypocrisy if he didn’t favor legal immigration. His father is an example of the best we can do: a guy who came here to escape a bad situation getting worse and eventually assimilated completely.
So Ted would be laughed at if he said “I think the 1965 act went too far” - he would be crucified by the Left.
It’s a weakness of his candidacy. And I’m sure he actually does believe that way. But regardless, he could never say so if he didn’t. And he’s smart enough to understand all that.