The state assembly of California maybe sees things differently to you.
They believe they implemented the Roosevelt policy when it was presented rather than take stand against it therefore were complicit. That is one reason why they probably apologised. Anti-Japanese sentiment was very high in those days so we do not know which sort of pressure the state of California was under and from which angles - but if they are complicit it stands to reason they should apologise.
The state of California was already discriminating against the Japanese as far back as 1913 when they passed the
Alien Land Law to stop them buying farmland and 7 years later in 1920 they passed a law to stop anybody with Japanese ancestry from buying farmland so maybe they were not under pressure from any political angle and instead were happy to implement their racist policies before, during and after the second world war and if that is the case then again an apology from them to their victims is probably something they wanted to do:
https://www.pressdemocrat.com/news/10732322-181/california-apologizes-for-japanese-american One solid reason why the state assembly shouldn't apologize is they were not responsible for the decisions, or the implementations of those prison camps. The federal government was.
Looking into it further, I think you are right on some points and so am I.
The approximate 1/3 of the group who were actually Japanese citizens - I do not see what could have been done with them except intern them.
For the others, it does appear CA had state - level racist policies.
https://en.wikipedia.org/wiki/Internment_of_Japanese_AmericansOf 127,000 Japanese Americans living in the continental United States at the time of the Pearl Harbor attack, 112,000 resided on the West Coast.[9] About 80,000 were Nisei (literal translation: "second generation"; American-born Japanese with U.S. citizenship) and Sansei ("third generation"; the children of Nisei). The rest were Issei ("first generation") immigrants born in Japan who were ineligible for U.S. citizenship under U.S. law.[10]
Japanese Americans were incarcerated based on local population concentrations and regional politics. More than 112,000 Japanese Americans living on the West Coast were forced into interior camps. However, in Hawaii, where 150,000-plus Japanese Americans composed over one-third of the population, only 1,200 to 1,800 were also interned.[11] The internment is considered to have resulted more from racism than from any security risk posed by Japanese Americans.[12][13] California defined anyone with 1/16th or more Japanese lineage as sufficient to be interned.[14] Colonel Karl Bendetsen, the architect behind the program, went so far as saying anyone with "one drop of Japanese blood" qualified.[15]