This video segment does a great job of showing how one retired cop explains away violence against unarmed peaceful protestors by saying that (a) there was violence someplace else, and (b) someone else shot police someplace else. Therefore, he argues, we should understand police beatings and tear-gassings at peaceful protests by unarmed people. You kind of have to see this to believe it.
The African American guest has it right: the retired white cop can't connect any of his grievances against those involved in violence against police with the violence actually witnessed by the guest. So he makes up explanations to get the conclusion he wants, which is that all the police violence is justified.
If the retired cop's view reflects that of active members of police forces around the country, it's no wonder there's escalating violence against civilians: cops feel tit-for-tat violence (and killings) is justified. No wonder people chant "No Justice, No Peace." And no wonder it makes thugs like the retired cop nervous. They intend violence and know they're the problem.