Possibly he knew that the Oakland PD is not up to the task of keeping order, and figured they'll take anybody, and/or he knew about the "Your Muslim Bakery" rampages and figured the lack of quick and widespread arrests of all involved meant that Oakland turns a blind eye to the typical efforts of the ROP.
CAIR was possibly poised to fund a legal battle on his behalf for being profiled as a Muzzie in being turned down for the Oakland police. Perhaps he couldn't document sufficient proof of that, or maybe he just couldn't muster a decent score on the exam.
HF