When I look up the word “senseless”, the first definition is something like “unconscious”, which suggests an element of thoughtlessness. So, while “senseless” can also mean “really stupid”, it doesn’t always.
Using the word “senseless”, then, to describe something like what happened in Charlottesville over the weekend, allows someone to think that these acts occurred without any intent, that things just somehow got out of hand. I doubt that that’s the case. A better term would be “moronic”.
My point is, we have to start calling these things what they are. Terrorism – yes. Heinous – yes. Senseless – no.