It was a State level Proposition as far as I am aware, so it isn't merely the case of one problematic DA. I could be misunderstanding something though.
The state level proposition does not require DAs to ignore shoplifting. It just turns it (and a few other crimes) from felonies into misdemeanors when the amount involved does not exceed $950.
Misdemeanor shoplifting can still earn up to 180 days in county jail and a fine of up to $1000, but only if a DA prosecutes.
What is the support for your statement?
Also “the DA” is a ton of different people throughout the Bay Area, and the DA that everybody complains about has exactly 0 HDs in his jurisdiction.