Gas explosions can flatten entire buildings, depending on how much gas was able to accumulate before being ignited.
Like, if gas slowly seeps into the rarely used basement, and even then, it's heavier than air (cmiiw) and often the particular "gas smell" is disguised by the musky old-basement smell. - The gas might remain undetected for days / weeks.
I don't see it as encouragement. A sad statement of fact. They are going to use this, like they use every tragedy that can be twisted to fit their world view.
Reminds me of when a gas leak caused an explosion near my old flat. Terrible stuff, and even though it was pretty high up, people were incredibly disrespectful by inventing theories about the "true" origin.