For comparison, UCSB (about 90 miles away) is about 20% Asian American.
A number of people would rank CalPoly SLO similarly to UCSB for some majors. The nearest high school to UCSB is about 7-8% Asian, but the other high schools in the area have significantly fewer Asians. The Santa Barbara area is mainly split between white and Hispanic.
So, you can compare Calpoly’s 11% to UCSB’s 20% to determine whether Asian students are attending SLO less that equally qualified students of other races. I’d agree that there is probably a perception among Asian parents that SLO is not as highly ranked because it is not a UC.