If we trained dogs to do exactly what police dogs are trained to do, we would end up in trouble, even if only in civil suits. If our dogs were trained to do what their dogs are trained to do, and did it to them, our dogs would be killed.
On June 28, 2018, a welfare check turned into a pursuit for a suspect. Nelson deployed his K9 and the K9 bit the original detective pursuing the suspect. Nelson commanded the K9 to release the detective, with his injuries from the attack rendering him unable to continue. Continuing the pursuit, Nelson rammed and tackled the suspect to the ground and the K9 bit the suspect. Nelson held the suspect in a vascular neck restraint. The K9 then bit Nelson.
They can even control their own dogs.
Seriously, there is a time and a place that a k9 maybe warranted, but it's not all the time, in every place.
On the hunt for a serial killer, sure.
Attacking someone for jaywalking? That should be investigated as use of excessive force, as much as it would if the cop beat the guy up himself.
Unrelated but, at one point Indianapolis had the highest incidents of being bit by a police K9 in the country. As it turned out they would let their dogs bite the suspect anytime they were called to the scene.