The failure to seek a change in venue from downtown LA to Santa Monica was a monumental blunder. The difference between the downtown LA juror pool and the Santa Monica juror pool is enormous. I'm not prepared to say it was the only reason for the acquittal, but it was absolutely a huge blunder by Garcetti. Police screw-ups and Fuhrmann's use of the N word certainly didn't help, but it would have been far easier for the prosecution to overcome those obstacles in Santa Monica.
You say "[t]he jury would not have unanimously found him innocent anywhere in the country if not for the police screw ups." I can think of lots of places in this country where a jury very likely would have found Simpson guilty notwithstanding the issues with the police handling of the investigation -- Simi Valley, for one. (BTW, criminal defendants are not found "innocent." In general, there are two possible verdicts in criminal cases -- guilty or not guilty. Depending on the jurisdiction, there might be other options like "not guilty by reason of insanity" or "not proven." But "innocent" is not a possible verdict in a criminal trial.")