Is Mariane a journalist as well or was she using the 'royal "we"'?
Whether this is purely her idea of journalism or was her husband's as well, wanting to "change the world" as a journalist would certainly seem to lead right to biased reporting (reporting only those "truths" that might influence the world to change in the way one wanted).
The statement about "ego purposes" is an odd one. Expecting to change the world all by oneself (through journalism, yet) sounds terribly egotistical to me. Mariane brings ego up and then denies it as a motivation. Interesting and revealing.
we chose it because we wanted to change the world
This is what angers so many people about the media and why so few trust them. If the goal is to change the world, they're admitting that they're going to slant their reporting to do so. I'm not sure that had anything to do with his death, but it doesn't seem impossible to imagine it having at least been on his murderers' minds...