This news is not about churches, but it made me think about it: http://www.bbc.com/news/world-europe-40140968.
This is a genuine threat, but imagine for a second a childish prick who would manufacture such a threat, to ruin a concert, of pop, of rock, of metal, which ever.
Burning a church is like carrying the terror attack.
Reveling in the prospect of the church burning, or promoting the concept, is the same as congratulating terrorists after such an attack, or posing as someone who would enjoy the prospect.
It is pretty much the same immature posing attitude.