is the idea of non-violence still current among activists?

4. NON-VIOLENCE

It is essential that we develop effective alternatives to society's current patterns of violence. We will work to demilitarize, and eliminate weapons of mass destruction, without being naive about the intentions of other governments. We recognize the need for self-defense and the defense of others who are in helpless situations. We promote non-violent methods to oppose practices and policies with which we disagree, and will guide our actions toward lasting personal, community and global peace.

http://www.gp.org/four_pillars_ten_key_values

One of the most mystifying things to me about the bus incident is the apparent acceptance by some that escalating to violence is an acceptable response to (alleged) verbal provocation. No matter how ugly or offensive something a person might say can be, physically assaulting the person is not consistent with Green values, or, if I'm not mistaken, most activists' values.