Why aren't more Republican politicians calling out the democrats directly for just letting millions of undocumented people walk in freely? What fucking nation on this Earth do you know of that wasn't in the middle of a collapse like Rome just let millions of unvetted people walk through their borders? Besides Eurocucks with refugees of course.
A few thoughts
1. I have heard them call them out, but, like you said, perhaps not as many as should.
2. Who would they call them out TO? The media is captured and wants to see the Republicans fail and the Democrats succeed (at least, for now). They often literally ignore Democrat scandals to protect them.
3. The Republicans still NEED "Latino" votes, thanks to every group not "White Men" voting in identity blocs. That means if they go too hard against the immigrants, they risk pissing off American Mexicans and that's a problem.
4. Many Republicans don't care about immigration other than that their constituents "make" them care. They'd much rather work on other goals, like insider trading, embezzlement, or maybe things that benefit their state and constituents.
5. Many Republicans are RINOs -- fake Republicans that exist only to enrich themselves at the expense of the citizenry, or literally are there to ensure a real Republican doesn't get the seat. They obviously aren't going to help
6. Changes to the status quo -- rocking the boat -- is bad for any politician, but especially bad if you're just trying to collect a paycheck.
7. Republicans have spent the past oh, 40 years being trained in learned helplessness -- "Nothing can be changed because the rules say nothing can be changed." To wit: "They're already here, what can we do about it?"
8. I remain convinced that many political advisors to even the actual Republicans that want to do things are compromised or are outright moles. They tell the Republicans that DO want to do shit to wait, to not risk it, that people don't REALLY want change, et cetera. For related examples, look to Ann Coulter on the right and Bill Maher on the left -- both are wormtounges that tell their respective audiences exactly what the power brokers behind the scenes want them to hear, while tricking them into thinking they're being independent.