Language changes and the dictionary definitions change too to keep up with the times. "Prejudice" used to simply mean to pre-judge. The military used the term correctly i.e. "Terminate with extreme prejudice". The military in essence was telling soldiers to pre-judge the situation and kill whomever was the unfortunate S.O.B. subject to the orders.

We all are prejudiced whether we mean to be or not. If you are walking down a city street at night and a loud group of black males appears in front of you, you will likely prejudge the situation. Even liberals do that. It's why they say nice things about blacks and Hispanics, while moving way from them. Even Jesse Jackson admitted he was relieved to hear someone coming up behind him only to turn around and realize that person was white.

Likewise, if a black person in a rural area sees a pickup truck with a rebel flag across the back window, an NRA bumper sticker, a "Don't tread on me" bumper sticker, they may pre-judge the vehicle's owner and decide not to solicit him for a donation to BLM.