We need to get the following questions answered before we can speculate any further.

1. Was the blast designed to kill a person, services or building.
2. Who and where (GPs) were people at the time and leading up to the explosion.
3. How do we get the "hacker known as 4chan" to unleash is weaponised autism to find these answers. These 2 questions will put us on the right path to knowing why this happened, everything else is speculation.