Do you think the Republican base thinks about this so seriously? There are two options:
- I have always been a Republican
- I hate brown people
That is their constituency.
The only way for them to recognize there is a problem is when a family member or them are detained by ICE or brutalized by police. Even then it is a gamble if they just say "there are some bad apples".
Right-wingers are unable to consider societal problems and systemic oppression.