I pretty much agree with you (since the 18 pages of arguing isn't over whether your post could be understood, it's really about well... people not actually engaging in, you know, the premise and idea and screaming about being criticised maybe a little bit and then bringing in fecking IQ of all things to try to disprove your point?!), but you did say:
That isn't reflective of what the INT score means; as problematic in aspects as it is, INT is more so treated as objective of a character's abilities. All of your other examples are fine, but this one wouldn't be covered by INT.
However, you are right in that people do often assume someone who is primarily speaks a different language or has a different culture to the place they currently find themselves in are often treated as if they are 'dumb' or 'stupid'.