Why are some US police forces equipped like military units?

[genxlib]

10. I hate seeing any inference that there is any kind of equivalence between those two problems.

The main difference is right there in text..."criminal".

All of that violence in Chicago and elsewhere is illegal. It will be investigated, prosecuted and punished to the greatest degree possible.

The primary problem with police violence is that it is often considered an acceptable part of the job and not prosecuted. Certainly it would be greatly diminished if there were consequences to their violence. If nothing else, there would at least be consideration that some sort of justice was served.