I read books and watch documentaries to help understand how and why people are swayed by propaganda, such as people who voted for obama and hillary. I also do social anthropology as a hobby.
Take yourself for example, rarely can you make a post without some kind of insult. If you worked for a news publication you could sway voters with your suttble jabs. Whether it is "Trump bad, sexist, racist...", or Goebells talking about the jews, the ideology (or concept) is pretty much the same, which is to spew as much misinformation as possible.
Another example is blaming the conservative right for violence, when the democrat party has a long, long, long history of violence.
I am sure this is falling on deaf ears, but I will keep going.
Take the lady in the opening post for example. I could go back and look at years of members here justifying killing a US citizen because of various reasons. The reasons are not "that" important. The important issue is the blatant disregard for human life.
Now that a woman is involved, I see fewer members justifying her murder than Anwar al-Awlaki.
The lady in the opening post held out for as long as she could, then started making emotional appeals. That does not excuse her crimes.
Personally, I would like to see all U.S. citizens who went to the middle east to be with ISIS brought back and put on public trial. Notice I said "to be with", rather than to fight for, or to fight with.
Take Albert Speer, Hitler's chief architect, for example. All he did was design stuff, yet he spent several years in prison. More or less guilt by association. The same should be done to the people who joined ISIS. Put them on public trial, let the evidence be presented, and let the public make up their own mind.