Are these the same supervisors who crafted the county sanctuary policies that killed Bambi Larson and then failed to make any changes in those policies?

I recall reading complaints about these sorts of things for the past two election cycles, and yet Sheriff Laurie Smith kept getting re-elected. I didn't really understand why. Do people just blindly vote for incumbents without doing any checking?

Why? People often vote for incumbents. Just because. (they are unaware or satisfied with the status quo). Or, most people are uncomfortable with change.
In US politics, it is most common, for people to give "Congress" a poor rating, but almost inevitably, give their very own local Congress member a good rating.
I would urge, if you are not sure of a politician (city council, school board, etc.) Then just don't vote for that position. Please do not just 'vote the incumbent'.

[I don't at all like Newsom's administrative abilities, I would like - but cannot get Any Other Democrat, I hate (R) Elder's policies ... therefore]