I don't think this shows what you think it does. I checked the demographics on a couple of the pink counties, and they were predominantly white. The Mexicans might outnumber the English, but they don't outnumber the English + the Irish + the Germans etc.
This is for biggest ethnicity per county.
In the overall state, Hispanics outnumber white people as of 2015.
http://www.latimes.com/local/california/la-me-census-latinos-20150708-story.html