These people don't view others as human. It's why they can cry about one of 'theirs' being killed but revel in the murder of a 'bad guy,' aka anyone who isn't firmly and vocally on 'their side.'

This is the result of programming, and unfortunately, many of these people have permanently gone off the deep end. These people can and some eventually will begin committing atrocities because they have dehumanized their political or ideological opponents, which justifies their rhetoric and the escalation of violence.