One is due to nature.
The other is due to stupidity.

The only reason we see cops running from the thugs is due to whatever rules of engagement they have or do not have. In this case the mayor "appears" to be in a timid, go easy mode. She being a black (simple fact) is in a delicate spot....by choice.

Where are the water cannons?
Where is all the military surplus assault equipment.

Of course all we can do is speculate based on what we read, view and hear.

One cannot be in response mode in a riot. The law needs to be in aggressive mode and put the thugs on the run. Tip toeing around being concerned how an action will play out in the media or the races is a definite disadvantage for enforcement. A situation very much in favor of the thugs and those who would exploit the situation.