I think you are mistaken in your application of the concept. Most people would not consider the reasonable expression of preferences to be "bigotry".
a: "I don't like getting proceed out of my own village by wealthy city dwellers buying holiday homes, and corporations buying up properties to use as Air BnBs"
b: Well that's because you are a disgusting bigot! You should be ashamed of yourself!
I will concede that I am using the term in a way that is typically not how it is applied, but I do think it hits at the root of the problem: humans struggle with cultural change.
My biggest concern is when we make assumptions that lead to violence and discrimination, in particular when it comes to minority groups, and there also where some of these groups have been historically mistreated.
Why do you see it as a positive thing that half of a class may have insufficient language skills to be able to deal with the curriculum?
The language skills may be sufficient, it would just mean learning a new language. This is in itself rewarding academically and culturally. The curriculum can be accommodated for. We do this with ESL students.
And that was the point. There are plenty of places where exactly this has happened, and immigration brings both positive and negative consequences.
One may legitimately oppose uncontrolled immigration for a variety of reasons that do not relate to racism of bigotry.
Possibly, but they need data for it. Regardless, we accept cultural change in one way that far outpaces the changes that come from immigration: technological and economic.