A Muslim protects lives and does not take them. The signs come in the wake of permanent terror attacks around the world. Islam is being abused, defiled, insulted and distorted into something unrecognizable by this. That's why it's good when Muslims make clear that they stand for peace and freedom, even when it is a little sad that they constantly have to justify themselves.
With respect to this, I often walked with my camera through Cologne, looking for quite different signs for peace and freedom, presented by Muslims.