Sorry but its not.
Just look at OPs title
The title is fine. We don't imagine the truck drove itself.
The real issue is the person behind it, and the potential motives because as much as we'd like to hope lone terrorists are isolated events, there's a remarkable pattern of radicalization even without physical connection or support infrastructure.
By all accounts (so far) they have no knowledge of this guy having direct ties to terror. We may, or may not, learn of any online contacts he had, but we'll never learn the full extent. What was preached back in Tunisia, in a local French Mosque, or what sympathies he carried for attacks on the news.
What we do know is there's a pattern of extremist ideology being carried in by immigrant, by refugee, by modern communications. Today the human condition of Tribalism is flourishing and clashing like never before. Because we've never been more open and vulnerable to those who hate us. And they've never had more direct communications back home.
This is the breakdown of assimilation, and through it, society.
And this is paid for in many innocent lives.