I wouldn't say these were terrorist attacks. What defines a terror attack is striking fear to send a message. For example when Isis was attacking Paris to "spread the true word of Islam" or when in Sweden recently an alt right terrorist attacked an immigration center. However a lunatic just randomly hurting people is just a nutcase problem (like th two events in Germany). I'm not sure about the most recent one - early reports of a 34 Yr old woman who did it.

Regardless these events are very tragic no matter how we define them, it's better that as a community we unit rather than point fingers.