Revenge is never a good answer! Why does this even need to be said?
If you wish to harm another person, for whatever reason, you are evil. If you enjoy or justify harm being done to another person, you are evil. The only possible justification for violence is immediate self-defence when you are attacked.
Any ethical system based on universal values would support this position. The problem is that we still have so many so-called ethical systems that are based on a group identity, such as nationality, ethnicity, or religion. These groups seem to consider their own members as better than the rest of the human race. As a result, they can justify treating non-members as less than human. This is evil.
I don't know how to solve conflicts, but I do know that revenge only makes things worse, leading to a never-ending vicious cycle of hatred. It doesn't matter who "started". How you respond to hatred and violence defines you as an individual and as a group. I hope the sane majority can pull back the extremists from the brink and prevent further violence and hatred. Things have already gone way too far in this conflict as it is.