It is supposed to be, but the administration organized a Massive Resistance campaign against the California Civil Rights Initiative. [0] Through mass 'holistic' review of individual applications for racial background, the University of California follows the same racial quota admission system that nearly all elite American universities do.
Not sure what this is in reference to, but as you can see at http://opa.berkeley.edu/uc-berkeley-fall-enrollment-data, UC Berkeley's freshman enrollment in fall 2015 was about 43% Asian (and, for comparison, 24% white), which does not indicate strong enforcement of racial caps in the manner suggested by tacon.
[I take no position in this post on whether the high representation of Asians, low representation of other American racial minorities, and decisions resulting in these outcomes are good or bad things (or deserve the label "meritocratic", or so on). I am simply noting that UC Berkeley seems similar to CalTech in all these regards.]
[0] https://en.wikipedia.org/wiki/Massive_resistance