I personally have never experienced unpleasant situations with the police or with security forces but many of my friends have. The older I become, the more stories I hear of police harassing Ethiopian youth without any provocation.
When you see police officers approaching Ethiopian men and asking them over and over to present their ID just because they happen to be in a park or walking on the street you can understand that something is very wrong. I was once the only Ethiopian Israeli waiting at a bus stop with other women and children; a police officer stopped me and asked what I was carrying. After I told him what I had with me–he went away. I only recently understood that the police can come after me too without reason.