>Sorry, I fail to see how asking to choose a specific geometric figure out of four can be culturally biased.
No, but whether that is a meaningful measure of intelligence is where the bias creeps in. In our times having high mathematical aptitude is considered to be a sign of intelligence and intelligence is associated with success, so the very same people who like mathy things design IQ tests and hand out credentials and make the most money, so the entire process is largely circular.
What constitutes intelligence is dependent on what environment you're in. If in 100 years all the technical things have been automated it's conceivable that people with high degrees of social intelligence or creativity who can leverage technology rather than implement it will get to define what intelligence means.