I think we have to be careful about how we react to disturbing incidents like this in the first few days. If we suspect it's terrorism then we should call it potential terrorism until it's confirmed/near enough confirmed, people should not rush to comparing to other incidents, even positive reactions such as multiple faiths coming together shouldn't be so ingrained that we eagerly wait for that positive display. We have time to quietly remember, stand together and mourn, and to investigate what is going on, but we do not need nessarily to rush into it. If we become too attached to our first opinion then we may fool ourselves out of a more informed opinion which develops later.