Nowhere did I say or suggest it was OK. I don't find looking at the past through a moralistic lens helps me understand it.
> People seem to be reacting pretty favourably to Ukraine's response to the current russian "migration".
The colonization of America much more closely resembled mass migration and then subsequent cultural conflicts than it did Russia's invasion of Ukraine. It didn't really resemble the latter at all.
> An assertion borne by absolutely nothing at best, and made as the US had just conquered the state and were looking to "pacify" it and fill it with settlers, made by the then holder of ultimate power in the state.
If you mean "conquering" California, you mean taking it from Mexico after the Mexican-American wars, California had already been subject to colonization efforts for almost a hundred years, but even so, I don't think speaking of the US federal government or the state government as "the holder of ultimate power" makes sense. Most people for a long time lived effectively free from any state control.
I mentioned the Comanche - it might be interesting to note that Comanche peaked in power just a decade prior to his term as governor, and they were in every meaningful sense militarily superior to the Americans, Mexicans, and surrounding native groups. They did not have a presence in California, but they're a good counterexample to the idea that natives just couldn't resist settlers - they rapidly acquired guns, horses, and often frankly superior skill in using them, which was frequently exercised. There's no doubt that settler encroachment and fundamentally incompatible ideas of civilization resulted in the pushing out and near-extinction of independent native communities, but it was by no means a sure, given thing. If native groups had united against the settlers and decided to get rid of them, they would have been wiped out.