An appeal against violence is a good idea; it is a basic Buddhist principle; and even in other religions, they often call for peace.
I remember a story (though the name of the king involved eludes me) where a king once asked Buddha Shakyamuni whether his country should go to war, and the Buddha said, we should never go to war.
Likewise, I think it is good to remember that as individual practitioners, whether we like the Shugden practice or not, that it is good to remember at these times, what the historical Buddha actually said; he asked for us to be peaceful, obviously. He asked for us to be compassionate; he also taught us not to be dogmatic. So if someone disagrees with someone else's practice, then I encourage them that they can just say the mani, and leave people alone. We may not always understand one another's practice; at any rate the important thing is our motive and our view combined with actions that overtly are non-violent, so that we can help all living beings and in so doing set a good example to the world. How do Buddhists resolve conflicts? Without violence, is the right answer, obviously. Of course this applies equally to all Buddhists, including Shugden Buddhists (yes, we are Buddhists, but even if someone doesn't think we are, the historical Buddha never taught to kill or physically harm non-Buddhists either; we are supposed to have compassion for all living beings).