Odinga seeks to weaken the police and thereby strengthen the Marxist agitators. Past Marxist revolutions have been crushed in the early stages by the police and military. If you hamstring them beforehand, the revolution has a better chance of success.
Most Americans have no idea of the importance of local control of law enforcement and just how much it protects them from federal tyranny. This is particularly true of sheriffs. Look at the example of the Colorado sheriffs who said they would not enforce the new gun control laws.
A police officer told me that one of their lessons in training was that they are not under the direct authority of the president. If the president were to them to arrest someone, they are to refuse the order.