It isn't just UCSD do not accept many international students, it is the public schools in California (in general) accept a lot less international applicants. All the schools in the UC system accepts fewer international students compare to private schools or public schools in other states.
If you want any numbers, Cal accepted 52 students in 2009 and only 2 of them are international, as far as I know.
And I'm pretty sure what you read about UCSD @ tgc is pretty accurate thus far.