Either they’re trying to cover for the mayor who told them to stand down, or they’re just a bunch of gutless cowards.
Neither reflects very well on them.
The SJ police definitely look bad but look at it this way:
Who in their right mind would want to be a LEO in a society that is coming apart at the seams, where life is cheap, where “the law” means nothing, where the highest office of the land despises you and can’t wait to prosecute you, and when the civil violence becomes a reality you are a potential target for two heavily armed opponents?
The police are going to stand by and watch the collapse, folks. The “Ferguson Effect” is alive and growing.