That's exactly correct, the mayor made them do it:
Originally Posted by Karl
We represent the 645 police officers who work hard every day to protect the citizens of Oakland. We, too, are the 99% fighting for better working conditions, fair treatment and the ability to provide a living for our children and families. We are severely understaffed with many City beats remaining unprotected by police during the day and evening hours.
As your police officers, we are confused.
On Tuesday, October 25th, we were ordered by Mayor Quan to clear out the encampments at Frank Ogawa Plaza and to keep protesters out of the Plaza. We performed the job that the Mayor’s Administration asked us to do, being fully aware that past protests in Oakland have resulted in rioting, violence and destruction of property.
Then, on Wednesday, October 26th, the Mayor allowed protesters back in – to camp out at the very place they were evacuated from the day before.
An Open Letter to the Citizens of Oakland from the Oakland Police Officers