That's normally true, and it may be the case here.
But I was able to see the news report, and the vandalism was very systematic. The vandals used a template and spraypaint. In the one church that I saw, the word "brainwashed" was spraypainted on just about everything, including every single step leading up to the church, perhaps to maximize cleanup expense.
My guess is college age or above --anarchists or the Occupy crowd. It didn't seem like the typical pointless swastika graffiti.