But only American citizens can vote. And I can't seem to find any data on the increase of the California population from naturalized citizens.
Prior to 65 immigration act, California was over 90% white.
By 2010, non-hispanic white was down to %40, hispanic ~%37%.
That is a huge demographic change. Hispanics nationally vote for Democratic/liberal politicians on avg. 70%.
So.. ergo, the dramatic blue turn California has taken politically can be accounted for by drastic change in demographics.
Your first statement is just restating the same premise: a dramatic change of the makeup of the electorate (whatever their "needs" or preferred political policies) changed the outcome of elections.
https://en.wikipedia.org/wiki/Demographics_of_California
section: "Population of California according to racial/ethnic group 1960–2010"
It places the individual's need, which are only incidental due to their current residence above the community's need. Whereas liberal-ish things tend to require something from every member of the community. (Less gun right, mandatory health insurance, more spending on refugees and unlucky folks, etc.)
Republicans have been trashing Hollywood and San Francisco/Berkeley for a long time, though.