It is simply the nature of sacramento. Government towns by and large tend to be more integrated than others. Look at DC. There was also a strong military presence in the city for quite some time. WW2 is really what prompted this once small farming capitol into a city. This helped add to the many different groups. the Pinoy, mexican, and chinese who used to do ag work traditionally, have established communities were newer waves of immigrant can come and make themselves at home.
In addition we have had a bay area exodus in which man middle class Blacks, Asians, and mexicans, and whites for affordable housing.
And for what ever reason, a sizable amount of Russians have settled out this way.
Check out how diverse McClatchy high is
Student Teacher Ratio C. K. McClatchy High School - Sacramento, California - CA