Major weldfuel explosions go through walls for no obvious reason

[Berrik]

I assume he was talking about the guy lighting the tanks being in little or no danger compared to the people hit by it, which I guess is problematic considering how low-effort and cheap fuel tank bombing is.

Bingo. It's an especially unfair tactic against blobs, as, while it won't kill the core, the blob has zero ways to do anything about it and it will remove a wide swathe.