I heard it differently: the most religious people in the world - jihadist Muslims - celebrated that fire. It seemed to them the triumph of their (true) god over your (false) god - both of whom like to show off with fancy houses, but neither cares much about kindness.
For the majority of atheists, severe damage to a fine example of medieval architecture is not funny - and I don't know any who "guffaw" - even if that architecture is a *monumental* waste of resources and man-hours, to the glory of church hierarchy at the expense of the poor French people of the time. Repairs will cost another fortune, but to the French people of today, it's beneficial as a landmark, a point of national pride and a tourist attraction.
Of course, jokes are made, by all kinds of people - but at least
some atheists are thoughtful, even about that.