Then no one should be able to "beat" the test and show no implicit preference.

There are two logical problems with this argument:

1. It's circular: All humans are racist because they're raised in a racist culture because all humans are racist because...

2. The existence of other exceptions to the proposed rule that culture defines us are entirely ignored. Is everyone capitalist because we're raised in a capitalist culture? Is everyone Christian because we're raised in a Christian culture?